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SPECIAL 

ANATOMY 



AND 



HISTOLOGY. 



WILLIAM E. HORNER, M. D., 

» « « 

PROFESSOR OP ANATOMY IN THE UNIVERSITY OF PENNSYLVANIA— MEMBER OF THE IMPERIAL 

MEDICOCHIROROICAL ACADEMY OF ST. PETERSBURG — OF THE 

AMERICAN PHILOSOPHICAL SOCIETY, &C. 



Multum adhuc restat operis, multumque restabit, nee ulli nato, post mille stecula 
prscluditur occasio aliquid adjiciendi. 

SENECA, EPIST. 



IN TWO VOLUMES. 
VOL. II. 

SEVENTH EDITION. 
WITH NUMEROUS ILLUSTRATIONS. 



PHILADELPHIA: 

LEA & BLANCHARD. 

1846, 






Entered, according to the Act of Congress, for the year 1846, by William 
E. Horner, in the Clerk's Office for the District Court of the Eastern Dis- 
trict of Pennsylvania. 



SPECIAL 

ANATOMY AND HISTOLOGY. 



BOOK IT. 



PART II. 

GLANDS— AND THE ORGANS OF ASSIMILATION. 

CHAPTER I. 

Prolegomena on the Structure of Glands. 

The intimate structure of glands was but imperfectly attended to 
previously to the celebrated Malpighi, who, in the year 1665, pre- 
sented to the world his work entitled Exercitationes de Structura 
Viscerum. Till his time the most minute inquiry had gone but little 
beyond the point of observation, that glands consisted, as an ultimate 
arrangement of their particles, in small granular bodies called Acini, 
from their being clustered like grapes or berries, growing very closely 
together around a common stem and its branches. 

The simple idea, propounded by Malpighi, is, that each acinus 
being a gland of itself, consists of minute spheroidal sacs, which re- 
ceive the secretion from the blood vessels. Darwin at a much later 
period modified this idea by advancing that the change occurred in 
the spheroidal sacs themselves. The celebrated Ruysch having im- 
proved much the art of injection, was enabled to show in his prepara- 
tions, that what Malpighi considered as sacs or follicles, were really 
formed of convoluted blood vessels. He hence adopted the opinion, 
false in itself, that the substance proper of glands, is formed wholly 
of blood vessels, and that the minute branches of the latter terminate 
Vol. II.— 2 



° ORGANS OF DIGESTION. 

by direct inosculation with the ducts of the glands. As another step 
in this inquiry, Mascagni and Cruikshank showed that the secreting 
canals in the mammary glands commence in the form of cells — and 
Professor Weber has discovered the same feature to exist in the 
structure of the salivary glands of birds and mammalia, and of the 
pancreas of birds. 

The existing state of opinions on this interesting subject, is de- 
rived from J. Miiller, Professor of Anatomy, Berlin, who* has an- 
nounced as the result of his inquiries on the structure of the secreting 
canals in all kinds of secreting glands, that such canals are found 
every where to form an independent system of tubes. " That whether 
they be convoluted, as in the kidney and testis, or ramified in an 
arborescent form, as in the liver and salivary glands — whether they 
terminate by twig-like coeca, as in the liver — or in grape-like clus- 
ters of cells, as in the salivary glands, pancreas and mammary glands 
— their only connexion with the blood vessels in all cases, consists 
in the latter ramifying and forming a capillary net-work on their 
walls and in their interstices: and that the finest secreting tubes, 
namely, those of the liver and kidneys, are always several times 
larger in diameter than the minute ramifications of the arteries and 
the veins." 

This doctrine is, therefore, a modified resumption of the more 
ancient one of Malpighi, and claims merely for the entire surface of 
secreting tubes what Malpighi thought to belong exclusively to their 
incipient extremities. The leading argument in its favour being, 
that in every case there is a minute vascular net-work of capillaries 
discernible on the parietes of these canals, and whose capillaries are 
much smaller than the secreting tubes themselves. f 

Glands of the most simple shape are mere recesses or pouches in 
the thickness of the membrane or surface to which they belong. 
(Folliculi.) In some instances they are very superficial and their 
bottom is reached through a wide orifice — in other instances their 
mouths are somewhat contracted like the neck of a bottle — in other 
cases they have a long and tortuous course (Tubuli) as the tubuli 
seminiferi of the testicle. In most of these modifications of a tubular 
arrangement, from the shortest to the most elongated, the walls of 

* De Gland. Struct. Penit. Leips. 1830. And Physiol, p. 185. London, 
1840. 

f See Capillaries. 



GLANDS. 7 

the tube are not absolutely uniform, but it will be found that there 
are either partial or cellular dilatations of it ; or ccecal-like appenda- 
ges, in great numbers discharging into it, and placed in varied an- 
gular relations to the principal sinus or secreting tube. The stem 
of a thickly clustering bunch of grapes, the berries being removed, 
will represent sufficiently well the mere mechanism of this arrange- 
ment. 

A form of secreting canal a little more complex is where a large 
spheroidal dilated sinus exists with tubules, radiating from it (Folliculi 
aggregati) in lines more or less regular; the sinus itself having a 
large patulous orifice connecting it, with the surface upon which it 
discharges. One of the follicles of the tonsil glands may represent 
this arrangement. Also the glandular linguales on the root of the 
tongue, which seem to be a mere extension of the lower end of the 
tonsil gland in the form of an expanded flank, and are not unfre- 
quently, directly continuous with the tonsil gland. Another form 
of this composite canalicular arrangement is when the collection of 
tubules is more in a line, the branches diverging more slightly from 
each other (Folliculi compositi) and each of those branches again 
diverging into other branches, and so on successively to their last 
twigs. The Meibomian glands and the vesicular seminales are in- 
stances of the linear composite follicle, or tube having but one set 
of branches. A lactiferous duct is an example of the composite 
secreting canal, or tube with a numerous and indefinite succession 
of finer and finer branches, and, which end finally in club-like dila- 
tations. Some of these secreting canals end in a divarication of 
branches resembling the flowering ends of the umbelliferous plants. 

Some of the glands present a species of regularity in the order of 
division of their secretory canals. The principal trunk of the latter 
gives off at intervals nearly uniform lateral branches, these branches 
give off with regularity other branches, and the latter again observe 
the same disposition. This modification is preserved to a remarka- 
ble degree in the pancreas, and is also visible in the salivary glands, 
the lachrymal, and the mammary. In cases of this kind the lobu- 
lated condition is very clear, the lobules being rather feebly held in 
connexion with the contiguous ones by loose cellular substance, 
allowing the lobules to be easily separated from each other by 
drawing at them. The lobules themselves are ultimately divisible 
into granules, (glomeruli or acini) which under the application of the 
microscope are found to be aggregated cells, surrounded by a fine 



O ORGANS OF DIGESTION. 

vascular net-work of capillaries, and making the peripheral end of 
the most minute secreting canals. The trachea with its division 
into bronchia, bronchioles, final air tubules, and air vesicles at the 
end of the latter, represents on a large scale the division which is 
seen in glands on a small one. An unsettled question is, whether 
these vesicular terminations are in all cases kept distinct, or whether 
from a defect in their parietes they do not communicate like the air 
vesicles of the lungs, and have in that way .a tubule common to 
several. In some instances the ultimate secretory tubules of those 
ramified ducts are arranged like cosca around the branches of the 
latter. 

Another form of the ramified secreting tube is where there exists 
no division of the gland into lobules, but it is resolved at once into 
acini. These acini being formed upon the final divisions of the 
secretory tube, which rise up in fasciculi, giving a brush like or 
penicillous appearance. The liver is an example of the above, it 
being doubtful whether there is any spheroidal enlargement at the 
free end of the penicilli.* 

The glands with successively ramified secreting tubes are the 

Lachrymal gland, 

Mammary gland, 

Salivary glands as Parotid, Sublingual, and Submaxillary, 

Pancreas, 

Liver. 

The glands of an almost pure tubular structure and indisposed to 
ramify, except in a very limited manner, are the 

Kidneys, 
Testicles. 

The Meibomian glands and the Vesiculse seminales may oe con- 
sidered as a tendency to the same structure, but in a more abbre- 
viated and simple condition; by some they are considered merely as 
branched follicles. 

* From peniculus a painter's pencil. 



GLANDS. i> 

The summary of the secretory glandular system then is, for it to 
present itself in the simple short tubular state of shallow depressions, 
or crypts of a mucous membrane as in the urethra and bladder ; — 
in bottle-shape cavities; — in closed lenticular cavities, as Peyers's 
Glands; — as the follicles of the alimentary canal which are either 
single or branched; — and as thin follicles with a glandular matter 
or parenchyma, principally vascular, forming a nidus around them, 
and which follicles may themselves be either simple or branched in 
some degree. 

The principal object of a secreting glandular structure would seem 
to be a development or augmentation of surface sufficient to the pur- 
pose of elaborating the quantity of the specific fluid called for ; in 
other words, for getting area for the requisite ends, like the display 
of surface in the interior of the lungs for air enough by respiration. 
The glands seem, therefore, as said by some, to be a sort of efflo- 
rescence from the surface, or cavity upon which they discharge ; 
being formed of canals with closed extremities as originally asserted 
by Malpighi. 

It is denied by Muller* that there are acini in any glands what- 
ever (the testes of some few fishes excepted) existing, as commonly 
understood, to wit ; as solid granules executing secretion, by means 
of their glomeruli of blood vessels having ducts arising from them, in 
an unexplained way. On the. contrary, he asserts, that acini are 
merely bundles of fine tubes formed by the ends of secreting canals, or 
frequently by collections of the vesicular terminations of the latter. 
The term acinus in its qualified sense is sufficiently proper, but 
it should be remembered that in receiving it according to its 
meaning, which is a berry or grape, the skin of the grape and its 
pedicle are alone to be understood, the pulp being omitted. 

In regard to the connexion with the blood vesssels, their cavities 
are as stated according to Muller; not to be considered as continu- 
ous with the cavities of the secreting tubes, but merely ramified on 
them by countless capillaries, the arteries simply terminating in the 
veins as in the case of the lungs, or, I may say, of the intestinal 
canal. This theory is however, almost too exclusive ; there are 
most probably organized porosities in the capillary system, I am 
disposed to think, in the venous especially, forming a communica- 
tion between the vessels and the canals on which they ramify; it is 

* Physiol, p. 501. 

2* 



10 



ORGANS OF DIGESTION. 



rather too easy to pass a minute injection from the capillary system 
into the canal upon which it ramifies, for us to suppose that every 
such case is one of rupture. We must, also, upon the ground of 
personal observation to the contrary, decline the opinion of Profes- 
sor Miiller, that there is no communication between the secretory 
ducts and the lymphatics. 

The cause of the massive character of many glands and of their 
shape may now be understood. The shape of glands must depend 
measurably upon the space and circumstances in which they are ac- 
commodated; the diversity of shape in the three salivary glands shows 
that this is a point of merely local convenience, and is subordinate. 
Their size, however, is upon another ground : this is regulated by 
the amount of secretion to be done, and by the necessity of this se- 
cretion being collected at one or more points. The process of as- 
similation requires the bile in the duodenum, only, and that in large 
quantity ; hence the liver is both a very large organ and all its secre- 
tion, is concentrated in one focus. If the necessity for the latter 
had not existed, the liver like the muciparous glands might have 
been disposed in small granules all along the alimentary canal. 
This hypothesis, by the way, will show how the liver or any other 
gland may exist in the form of insulated acini without the function 
being altered ; and also show the reverse, how if all the muciparous 
glands were collected into one mass for the purpose of having a focal 
point of discharge; that this arrangement would require also a single 
large duct made by the successive junction of branches, just as in 
the liver. 

As the vascular capillaries ramify upon the parietes of the secre- 
tory tubes, so, their parent branches are found in company with the 
larger branches of the latter. The development of the two systems 
is found to be simultaneous. The tubes are first of all planes, then 
simple canals or coeca, then primary branched canals or cceca, then 
undergoing an indefinite series of divisions. At first these canals 
are loose and unconnected, but as the evolution of the gland ad- 
vances they cohere and become consolidated; but at every period 
of development and of perfection, the capillaries form a net-work 
around them smaller than the tubes themselves. 

There is no essential correspondence between the construction of 
a gland and its secretion. Very different glands have similar struc- 
ture, as the testes and the kidneys, and similar glands have a 
varied secretion in different animals. The liver in one animal is 



GLANDS. 11 

simply in the form of cceca, in another of tufts of coeca ; in others 
of branches of cells or of a spongy tissue, or as a branched duct 
having terminal twigs like a feather. The testes are indefinitely 
varied ; the kidneys alone maintain a constant character. The con- 
struction of a gland is always regulated by the special demand upon 
it by the condition of the animal in question; hence the salivary 
glands are exceedingly simple in birds and serpents ; the pancreas 
in fish; and the liver in the lower animals. Where more surface is 
required, then new processes from the main line of the secreting 
tube spring up. 

Recent microscopic observations have ascertained other new points 
in glandular structure. Purkinje remarked, that the walls of all se- 
creting cavities or canals are formed by nucleated granules, of the 
diameter of m-hoX) of aline, making, according to his phraseology, the 
glandular Enchyma, product, or Jluid. With the aid of Schwann and 
Henle this arrangement has been found in all the glands and over 
the entire mucous surface, constituting in fact a cellular nucleated 
epithelium, which is now thought to execute the specific secretion ot 
all glands. 

The determinate physiological doctrine of the day, may be then 
summed up, in the general declaration, that, whatever be the secre- 
tion in question, it is elaborated through the growth and nutrition of 
cells covering the free surface of excretory tubes, and their branches 
to their very end. So far as the microscope can avail, there appears 
to be no difference between the structure of the cells of one secre- 
tion and those of another. Their capacity to eliminate from the 
blood the specific secretion, is one of those abstruse acts of the sys- 
tem, depending upon an original endowment; a dictum in other 
words, of that creative energy which spoke all things into existence, 
and still continues to retain them in it. In a case of this kind we 
may possibly rest contented with the wisdom of a former period. 
Omnino autem cum Deus oliquid facit, nulla opus est ratione. Quo- 
modo nos ex nihilo fecit?* 

Biliary matter and oil are easily recognised in the above cells of 
the liver, by their difference of colour, and by their refracting powers: 
— milk is detected in a similar manner in the mammary gland; seba- 
ceous matter in the follicles of the skin, and so on of other glands. 

The above cells having reached a state of maturity, and accom- 

* St. Joannes Chrysostome. 



12 ORGANS OF DIGESTION. 

plished a perfect secretion within their own cavity so as to fill it, this 
secretion is discharged by their dehiscence, or dissolution, and is 
then conveyed to the point where it is wanted. The generation of 
secreting cells, thus exhausted, is succeeded by another generation, 
and so the process goes on during the life of the individual. It is 
thought that in some glands this succession is diffused over the whole 
free surface of the excretory tubes, but in others that it is confined to 
the extreme end or terminus.* 

There are some other organs called glands, but they differ from 
the preceding in having no excretory ducts. They are supposed 
to be limited in their function to the modifying in some measure, the 
fluids going through them. One kind of them is formed essentially 
of blood vessels, and they are called Ganglia sanguineo-vasculosa; 
of these we have the spleen for the chylopoietic system ; the cap- 
sular renales for the kidneys ; the thymus and thyroid gland for the 
organs of respiration, and the placenta for fcetal life. The second 
kind, called lymphatic glands, [Ganglia lymphatico-vasculosa,) con- 
sist essentially of lymphatic vessels entering on one side and de- 
parting at the other, after having divided into branches and cells in 
the thickness of the gland. There are also other glands whose cha- 
racter and functions are still more doubtful, they being found in con- 
tiguity with the encephalon, as the Pituitary gland, the Pineal, and 
the glands of Pacchioni. 

The real glands on the contrary not only modify the blood which 
circulates through them, but give rise to a new fluid as a consequence 
of the transformation of the blood ; and this new fluid is discharged 
for a specific purpose by its efferent tubes into contiguous canals or 
places. 



CHAPTER II. 

Of the Abdomen Generally. 

The cavity of the abdomen occupies the space between ihe infe- 
rior surface of the diaphragm and the outlet of the pelvis ; a con- 

* Goodsir, see Carpenter Elem. Physiol., p. 409. Phila. 1846. 



OF THE ABDOMEN. 13 

siderable part of it is, therefore, within the periphery of the lower 
iibs above, and of the pelvis below. It is completely separated 
from the cavity of the thorax by the diaphragm, with the exception 
of the foramina in the latter, for transmitting the aorta, the ascending 
cava, and the oesophagus. It is bounded, below, by the iliaci interni, 
the psoas, and the levatores ani muscles ; on the front and sides by 
the five pairs of muscles called abdominal ; and behind by the lesser 
muscle of the diaphragm, the quadrati lumborum, the lumbar verte- 
brae, and the sacrum. The figure of this cavity is, therefore, too ir- 
regular to admit of a very rigid comparison with any of the common 
objects of life ; but a little reflection, on the course of its parietes, 
will make it perfectly understood. It should be borne in mind, 
that the very great projection of the lumbar vertebra? forms for it a 
partial vertical septum behind ; which, in thin subjects, is almost 
in contact with the linea alba in front, and may be easily distin- 
guished through the parietes of the abdomen, when the intestines 
are empty. 

The abdominal cavity varies only, inconsiderably, in its vertical 
diameter, owing to the resistance of the diaphragm above, and of 
the pelvis below ; neither does it change behind, owing to the resis- 
tance of the spine, the ribs, and the muscles there. But as the in- 
troduction of food, the development of gaseous substances during 
digestion, the evolution of the foetus, and many other conditions, re- 
quire some provision for its undergoing an easy augmentation of 
volume ; the latter occurs principally forwards and laterally, by the 
yielding of the muscles and by the extension of their aponeuroses. 

The diaphragm and the abdominal muscles, for the most part, 
act alternately ; as the former descends in inspiration the latter 
relax and give way to the contents of the abdomen ; but in expira- 
tion, the abdominal muscles contract, and the diaphragm is pushed 
upwards by the viscera. In attempts at the expulsion of faeces, and 
in parturition, these muscles contracting, aud the diaphragm being 
fixed all at the same moment, the cavity of the abdomen is actually 
much diminished. 

The viscera contained in the cavity of the abdomen are of three 
kinds. One kind is engaged in digestion and assimilation ; another 
in the secretion and excretion of urine ; and the third in generation. 
As these viscera are numerous, and it is of great importance to 
determine with precision their position and relative situation, ana- 
tomists are agreed to divide the cavity of the abdomen into several 
arbitrary regions. This is the more advantageous, as the bony 



14 ORGANS OF DIGESTION. 

prominences bounding the abdomen are not sufficiently numerous 
and distinct, to afford those obvious points of relation to the vis- 
cera which are furnished in other sections of the body. To obtain 
these regions,* consider a line or plane as extending across the ab- 
domen, about two inches below the umbilicus, from the superior 
part of the crista of one ilium, as it appears through the skin, to 
the corresponding place of the other side. Strike on each side a 
line perpendicular to the preceding, by commencing at the lower 
end of the anterior inferior spinous process of the ilium, and car- 
rying it up to the diaphragm. Extend a fourth line across the ab- 
domen parallel with the first, and intersecting the last two where 
they come upon the cartilages of the false ribs. It is evident that 
these four lines or planes, two horizontal and two vertical, will, 
with the assistance of the parietes of the abdomen, furnish nine re- 
gions: three above; three in the middle; and three below. The 
central region, above, is the Epigastric ; and on its sides are the 
right and the left Hypochondriac. The central region in the mid- 
dle, surrounding the navel, is the Umbilical ; and on its sides are 
the right and the left Lumbar. The central region below, is the 
Hypogastric; and on its sides are the right and the left Iliac. 
There are also some subordinate divisions : for example, the hollow 
in the epigastric region, around the ensiform cartilage, is called 
the pit of the stomach, or Scrobiculus Cordis ; and for an inch or 
two around the symphysis pubis, is the region of the pubes, (Regio 
Pubis.) 

Anatomists differ among themselves about the points of depar- 
ture and the position of the lines, or rather planes, separating the 
regions. Some fix them at definite distances from the umbilicus, 
and others resort to the points of the skeleton. The umbilicus is 
the most fallacious mark, because its elevation varies considera- 
bly, according to the state of distention of the abdomen, it being 
comparatively higher when the abdomen is tumid than when it is 
not. Neither does it answer to take the anterior ends of the last 
ribs as the points for the upper horizontal line to pass through ; as 
they, sometimes, are almost as low down as the umbilicus itself. 
The superior anterior spinous processes are also objectionable as the 
points of departure for the vertical lines ; as they leave too much 
room for the central regions of the abdomen, and too little for the 
lateral : I have, therefore, after some hesitation, thought it proper to 

* Anat. Atlas, Fig. 297. 



OF THE ABDOMEN. 15 

substitute the anterior inferior spinous processes ; and, especially, as 

the position of the viscera, according to almost universal descrip- 
tion, is more in accordance with this rule. 



General Situation of the Viscera of the Abdomen* 

When the abdomen is so opened as to leave its viscera in their 
natural position, they will be found as follows : — 

1. The Liver, the largest gland of the body, is in the right up- 
per part of the abdomen, immediately below the diaphragm. It 
occupies nearly the whole of the right hypochondriac region ; the 
upper half of the epigastric ; and the right superior part of the left 
hypochondriac. The anterior extremity of the gall-bladder pro- 
jects beyond its anterior margin. 

2. The Spleen is situated in the posterior part .of the left hypo- 
chondriac region. 

3. The Stomach, in a moderate condition of distention, occupies 
the lower half of the epigastric region, and the right inferior portion 
of the left hypochondriac. 

4. The Small Intestine, when moderately distended by flatus, 
occupies the umbilical region, the hypogastric, portions of the iliac 
on each side, and also the upper part of the cavity of the pelvis, 
when the viscera of the latter are empty. 

5. The Large Intestine traverses the cavity of the abdomen in 
such a manner as to perform almost the entire circuit of it. It be- 
gins in the right iliac region by receiving the lower extremity of the 
small intestine ; it then ascends through the right lumbar and the 
right hypochondriac, passes into the lower part of the epigastric, or 
into the upper of the umbilical, according to the state of distention 
of the stomach ; thence it gets into the left hypochondriac, being 
fixed higher up there than in the corresponding region of the other 
side ; afterwards it goes down into the left lumbar and into the left 

* Anat. Atlas, Figs. 299, 300, 301, 302. 



16 ORGANS OF DIGESTION. 

iliac, -where it makes a large long loop, called its sigmoid flexure ; 
thence it passes into the pelvis, in front of the left sacro-iliac junction 
and inclining afterwards to the central point of the sacrum, it sub- 
sequently descends in front of the sacrum, and coccyx to terminate 
in the orifice called anus. 

6. The Caul, or Omentum, is a membrane, of various densities, 
in different individuals, and lies in front of the intestines. Some- 
times it is found spread over the latter like an apron, but on other 
occasions is drawn up into the umbilical region, forming a ridge 
across it. It is attached to the stomach and large intestine. 

7. The Pancreas lies transversely in the lower back part of the 
epigastric region. It extends from the left hypochondriac region to 
the right side of the spine, and is placed behind the stomach, so as 
to be covered by it. 

8. The Kidneys and the Capsulae Renales, each two in number, 
are placed in the posterior part of the lumbar region on the side of 
the spine. 

9. The Urinary Bladder and the Rectum, in the male occupy the 
cavity of the pelvis, and in the female between them are placed the 
uterus, the ovaries, and the vagina. 

As, in the dissection of the abdominal viscera, the subject is com- 
monly placed on its back, so the preceding description is made out 
with a strict reference to that position. Some modification in the 
shape of the abdomen, as well as in the situation of its contents, 
occurs in standing upright. The front of the abdomen becomes then 
more protuberant, the lumbar vertebrae make a greater projection 
forwards. The pelvis is also so adjusted, in order to bring the ace- 
tabula directly in the line of support to the spine, that the convexity 
of the sacrum presents almost upwards, and the superior strait looks 
forwards and upwards towards the navel, so that much of the weight 
of the viscera is thrown upon the pubes. In this attitude most of 
the viscera descend, but more obviously the liver, from its weight 
size, and solidity. Portal has verified this descent by comparing 
the thrusts of poignards into the liver in the erect, with those inflicted 
in the horizontal position. He also asserts that the same may be 



ORGANS OF DIGESTION. IT 

ascertained in the living body by applying the fingers under the false 
ribs, and then directing the person to change from the recumbent 
into the vertical position. The spleen affords the same results when 
it is slightly enlarged, and the descent of the liver and spleen will of 
course ensure that of the stomach and intestines. According to 
Winslow, the pain and faintness which are felt after a long absti- 
nence, come from the vacuity of the stomach and intestines, which 
thereby withdraw their support from the liver, and permit it to drag 
upon the diaphragm. 

The presence of flatus in the stomach and intestinal canal, seems 
to be entirely natural to them ; for it is comparatively rare to find 
them destitute of it, even when they contain no food or faeces. The 
large intestine is, however, more frequently found contracted or 
empty than the small. Owing to the flexible character of a con- 
siderable portion of the abdominal parietes, the latter, by their own 
contraction, as well as by atmospheric pressure, are kept in close 
contact with the viscera; and the viscera again, by the same influ- 
ence, are kept in close contact with one another ; so that, notwith- 
standing the irregularity of their forms and the fluctuating size of 
the hollow ones, there is no unoccupied space in the cavity of the 
belly. 

Several instances are reported by anatomists, in which a total 
transposition of the abdominal viscera, has occurred, so that those 
which belonged to the right side were placed in the left.* They 
are, however, exceedingly rare. In the entire observation of my 
life, amounting to thirty-five years of anatomical study, and extending 
itself to many hundred bodies, I have not met with one instance 
of it. 

* Portal. Haller. Sandifort., &c. 



Vol. II.— 3 



18 ORGANS OF DIGESTION. 

CHAPTER III. 

Of the Peritoneum, and Serous Membranes, Generally. 

SECT. I. OF THE PERITONEUM.* 

The sides of the abdomen are lined, and its viscera are covered 
by a membrane called Peritoneum. As the reflections of this mem- 
brane, by being thrown over the periphery of almost every viscus of 
the abdomen, consequently, assume the same shape ; and as it lines, 
without exception, the interior surface of every part of the abdomen, 
its form is extremely complicated, and can only be judged of accu- 
rately after the study of the viscera is completed. For the present 
it will only be necessary to give the outline of it, leaving the details 
to each appropriate occasion. 

In man, it is a complete sac, having no hole in it ; but in woman, 
its cavity communicates externally through the Fallopian tubes. It 
has a double use : In consequence of covering the viscera, it is so 
reflected from them to the sides of the abdomen, that its processes 
keep the viscera in their proper places, and, therefore, answer as 
ligaments: again, its internal surface being smooth, indeed, highly 
polished, and continually lubricated by a thin, albuminous fluid, cor- 
responding with the synovial membrane of the joints, the motions 
which the viscera have upon each other in exercise, and in the per- 
istaltic action of the bowels, are much facilitated. 

The manner in which a double night-cap is applied to the head, 
will afford the easiest conception of the reflections of the peritoneum. 
If there were only one viscus in the belly, and that of a somewhat 
regular outline, as the spleen, the comparison would be rigid, and 
perfectly appreciable. One part of the cap is close to the head, and 
compares with the peritoneal coat of the spleen ; the other is loose 
and is equivalent to the peritoneum, where it is in contact with the 
parietes of the belly. It is also evident from this, that none of the 
viscera can be said to be within the cavity of the peritoneum • that 
they are all on its outside ; and that a viscus, in getting a coat from 

* Anat. Atlas, Fig. 298, 



OF THE PERITONEUM. 19 

the peritoneum, merely makes a protrusion into its cavity. Start- 
ing with this simple proposition, it is easy to conceive of a second, 
a third body, and so on, deriving an external coat from a protrusion 
into the same sac. Admitting these bodies to be spheres, the pro- 
position is immediately intelligible ; and, as a last step from it, 
the idea is not rendered much more complex by substituting any 
bodies even the most irregular in form, for these spheres. 

Such, then, is the fact in regard to the stomach, intestines, &c. ; 
they all, with the exceptions to be stated, derive an external coat 
from the peritoneum. 

The Peritoneum is, for the most part, smoothly spread upon the 
interior surface of the abdominal muscles. It adheres to them with 
considerable firmness by means of intervening cellular substance : 
this adhesion, where it closes the posterior opening of the umbilicus, 
is unusually strong. Below, the uniformity of the membrane as it 
descends from the navel to the pelvis is interrupted by its being re- 
flected over the urachus, and over the remains of the umbilical artery 
on each side. Where the urachus is, it forms an oblong prominent 
ridge, reaching to the upper extremity of the bladder ; and, as re- 
gards each umbilical artery, the duplicature is of a variable breadth 
in different individuals ; but always forms a well marked falciform 
process, reaching from near the umbilicus to the lower side of the 
bladder, and dividing the inguinal region into two parts or fossse, 
one next to the pubes, and the other near to the ilium. In the un- 
distended state of the bladder the peritoneum reaches to the pubes, 
is reflected from the latter to the upper, and then goes over the pos- 
terior surface of the bladder. In the male, it goes from the posterior 
lower end of the bladder to the rectum, but, in the female it does not 
descend so low there, and passes from the bladder to the vagina 
and uterus, and afterwards to the rectum. 

In the concavity of the ilium, and in the lumbar region, the peri- 
toneum is attached by long loose cellular substance, which permits 
it to be stripped off easily, simply by tearing. In these several re- 
gions it encounters the colon, over which it is reflected, and thereby 
forms the Mesocolon ; thence it passes in front of the kidneys, but 
separated from them by a thick layer of cellular and adipose matter, 
and immediately afterwards it is thrown into a long duplicature, ex- 
tending obliquely across the lumbar vertebras from above, down- 
wards, and to the right side. This duplicature includes the small 
intestine, and is the Mesentery. 



20 



ORGANS OF DIGESTION. 



In the highest regions of (he abdomen, the peritoneum is in the 
greater part of its extent uniformly reflected over the concave surface 
of the diaphragm, and adheres so closely to it, as to require a cau- 
tious and protracted dissection for its entire removal. As the re- 
mains of the umbilical vein of the fcetus are still found, but in a 
ligamentous condition, going from the navel to the under surface 
of the liver, their existence gives rise to the falciform ligament, a 
broad duplicature of peritoneum, which passes from the upper half 
of the linea alba and from- the middle line of the diaphragm to the 
liver. Another line of attachment, or of reflection, of this membrane 
to the liver, is found all along the posterior margin of the latter. In 
the same region, it is also reflected from the diaphragm to the spleen 
and to the stomach. Such is the general account of the course of 
the peritoneum. Each of the duplications has a distinct name, and 
some peculiarity of organization or of relation, which will require 
a specific description and a frequent allusion to it. 

It is proved, from what has been said, that the peritoneum is a 
single and complete sac, and that, with the exception stated of the 
Fallopian tubes, there is no hole in it either for the passing of blood 
vessels, nerves, or viscera. And that it is so folded over the abdo- 
minal viscera, that with patience and sufficient address, one might 
remove it from their surface and extract them, without even laying 
open its cavity : an experiment said to have been successfully ac- 
complished by Nicholas Massa,* and some other anatomists. 



SECT. II. OF THE OMENTA, f 

There are four processes of the peritoneum, each of which is 
designated under the term Omentum, Epiploon, or Caul. 

1. The Omentum Minus or Hepatico-Gastricum, extends, as its 
name imports between the liver and the stomach. It begins at the 
transverse fissure of the liver, proceeds from it, and from the lobulus 
spigelii, the front of which it conceals; and then continues to arise 
along the left margin of the base of this lobule to the back part of 
the liver until it reaches the diaphragm ; it also arises from the inferior 
face of the tendinous centre of the diaphragm along its posterior 

* Anat. Liber Introduct. an. 1539. Portal. 
f Anat. Atlas, Fig. 299. 



OF THE OMENTA. 21 

border, by its lower margin; it is attached to the lesser curvature 
of the stomach in all the space between the cardiac and the pyloric 
orifice. Its right margin reaches beyond the pylorus to the duo- 
denum, and includes the vessels going to the liver, and the biliary 
ducts; in consequence of which, this margin is called the Capsule 
of Glisson. The capsule is, however, more properly the condensed 
cellular substance within. 

The two laminae which compose the omentum minus are thin and 
transparent, and have but little fat in them; in approaching the 
stomach they become very distinct from each other, and receive 
between them the superior coronary vessels of the stomach. One 
lamina then goes before the stomach and the other behind, in the 
form of a peritoneal covering. These laminae, having covered in 
that way the anterior and the posterior surface of the stomach, unite 
again on the greater curvature of the latter, to form the beginning 
of the omentum majus. 

2. The Omentum Majus or Gastro-Colicum, as indicated by its 
name, is connected at one end all along the greater curvature of the 
stomach, and by the other along the transverse part of the colon. 
As it commences by two laminae, so it is continued throughout in 
the same way. It is commonly found more or less spread on the 
front surface of the small intestines, but occasionally it is tucked up 
in the epigastric region. When fairly spread out, either naturally 
or artificially, its course will be found as follows: It first of all de- 
scends from the stomach to the pelvis; it then turns upwards, so as 
to reverse its course, and* continues to ascend till it reaches the 
colon. Its two laminae then separate and receive the colon between 
them, so that, in this respect, the arrangement is entirely conforma- 
ble to what happens to the stomach. The subsequent continuation 
of these laminae is the mesocolon, which will be more particularly 
described. 

As the omentum majus consists of two laminae in its whole extent, 
it is clear that it resembles a flattened bag lined by another bag; so 
that in its whole thickness, when held between the fingers, there 
are four laminae. It is an irregular quadrilateral membrane, which, 
in corpulent subjects, is interspersed with a great deal of fat; but in 
such as are emaciated, it is wholly destitute of the latter; and instead 
of being entire in its parietes is a delicate reticulated membrane, so 
that the rule about the integrity of the peritoneum is not fully ac- 

3* 



22 



ORGANS OF DIGESTION. 



curate as applied to this section of it. On the right side it is con- 
tinuous with the omentum colicum, and on the left with the omentum 
gastro-splenicum. 

3. The Omentum Colicum may be considered as a continuation 
of the omentum majus along the ascending and a part of the trans- 
verse colon. In some rare' cases, (for in my own observations I 
have not met with the arrangement,) its origin is continued down- 
wards to the coecum, and at its left margin is extended along the 
transverse colon to the spleen. Much more commonly it is, as 
stated, simply an appendage of the great omentum, or its right 
flank, advancing for a short distance along the ascending colon. 

It consists of but two laminse in all, commonly containing fat, but 
in this respect subject to the same rule as the omentum majus. 

4. The Omentum Gastro Splenicum is the left flank or margin 
of the omentum majus, extended from the great end of the stomach 
to the spleen. It of course consists of but two laminge, which con- 
tain between them the splenic vessels and the vasa brevia. 

By looking for the posterior end of the gall-bladder, and then 
passing a finger under the right margin of the hepatico-gastric omen- 
tum, or in other words, under the capsule of Glisson, where it ex- 
tends from the liver to the duodenum, the finger will be found to 
have insinuated itself behind the stomach, and, by being directed 
downwards, will be thrust into the sac or cavity of the great omen- 
tum. In children, where the latter is less reticulated than in adults, 
and consequently more entire, a large blow-pipe introduced at the 
same point will enable one to inflate this cavity, and to separate its 
anterior from its posterior wall. This aperture, called the foramen 
of Winslow, is the route by which the internal or lining lamina of 
the omentum majus is introduced, so as to make this process of peri- 
toneum double throughout its whole parietes. Though this fact of 
duplicity is generally conceded, no author heretofore, to my know- 
ledge, has pointed out satisfactorily the means ; and for the sug- 
gestion of it, I am indebted to a. learned and zealous member of 
the profession, now Professor Hodge of the University. Struck, at 
an early period of his studies, with the difficulty of tracing a double 
sac to the omentum majus, out of a single membrane of the peri- 
toneum, this suggestion was happily made by him to remove the 
difficulties of other explanations. An attempt at at diagram formed 



OF THE OMENTA. 23 

upon any other principle I have invariably seen to fail. If the 
reader has conceived the idea, the inference will be plain, that the 
lining lamina of the omentum majus is continued as a common peri- 
toneal covering over the posterior face of the stomach, and then forms 
the posterior lamina of the hepatico-gastric omentum. It will also 
be plain that the same lamina, having reached the colon in its re- 
turn, continues afterwards as the upper lamina of the transverse 
mesocolon. 

From what has been said concerning the general qualities of the 
peritoneum, it is to be understood that though it enjoys much power 
of gradual extension, nevertheless this quality is not sufficient to 
enable it to endure, without a special provision, the sudden and 
extensive dilatations to which the stomach and bowels are ex- 
posed, from the introduction of food and from the evolution of gases 
during digestion. Of all the coats of these organs, it is the least 
extensible and contractile ; its rupture, therefore, is guarded against 
by one invariable rule. For example : as the muscular and other 
coats of the stomach dilate, the peritoneum is drawn from the omen- 
tum minus and majus to cover the stomach ; therefore, as the sto- 
mach enlarges, the omenta diminish: and as the stomach decreases, 
the omenta, by the restoration of peritoneum, resume their primi- 
tive size. In this way the uterus, notwithstanding its great aug- 
mentation in the progress of pregnancy, still keeps itself covered by 
peritoneum, from the ability of the latter, as mentioned, to slide 
from one part and to apply itself to another. The true intention, 
then, of the apparently useless length of many processes of the peri- 
toneum, is explained, by their being a provision for the augmenta- 
tion of the hollow viscera of the abdomen, in the discharge of their 
natural functions. Adopting this explanation as the basis of our 
observations, we shall find that according to the probable or even 
possible augmentation of a viscus, so are its peritoneal attachments. 
The stomach, which next to the uterus enlarges more than any other 
viscus, gets its subsidiary supply of peritoneum from the length of 
the omentum minus and majus; the colon, which is next in order, 
is supplied from the length of its mesocolon ; the small intestines, 
which are next, from the length of the mesentery. The latter, how- 
ever, would be too long for that simple purpose ; but the objection 
is removed by recollecting that the mesentery has also to accommo- 
date numerous chains of lacteal glands, through which the chyle 



24 



ORGANS OF DIGESTION. 



must pass in its elaboration, before it is fit to enter into the general 
circulation. The liver, being of a size almost stationary, has its 
peritoneal attachments proportionally short ; and its peritoneal co- 
vering, from the shortness of the connecting cellular substance, is 
disqualified from sliding. The spleen is in the same predicament 
with the liver, except that its size is not stationary ; but in this 
case, the peritoneum presents a phenomenon entirely remarkable: 
it wrinkles upon the contraction of the spleen. 

If this mode of reasoning, derived, from an arrangement of parts 
which no one denies, be correct, it follows that physiologists have 
erred sadly in the supposed uses of the omentum majus. That 
this organ is, in fact, only subsidiary to the enlargement of the 
stomach and colon, so as to prevent the rupture of their peritoneal 
coat, and that it is neither intended to keep the belly warm, as so 
learned a naturalist as M. G. Cuvier has suggested,* nor is it a 
special store-house for the wants of the system during the destitu- 
tion of other aliment, farther than adipose matter in other parts of 
the body is.f In regard to the first theory, it does not appear that 
the inhabitants of cold climates are better furnished with an omen- 
tum majus than those of the torrid zone: that it is better developed 
in winter than it is in summer ; that it is tucked up in warm 
weather to cool the intestines, or spread out in cold weather to 
make them more comfortable. On the contrary, it is ascertained 
that its position is variable at all seasons ; that in the coldest of 
weather it is as often found collected in the epigastric region, or to 
one side of the abdomen, as it is in the warmest ; consequently, its 
position is the result of whatever motions may, for the time, have 
been impressed upon it by the distention of the stomach, and by the 
peristaltic movements of the bowels. In regard to the theory of Dr. 
Rush, this objection is insurmountable ; that children, who are equal- 
ly, if not more exposed to starvation and sickness than adults, never 
have fat, except in very small quantities, in the omentum, and that 
only along the course of its vessels. The fat is, therefore, not to be 
viewed as an essential circumstance in the structure of the omentum, 
as all children and many adults have it only very sparingly ; for the 
omentum being wanted as a membrane of reserve to the stomach 
and colon, the deposite of fat in it, is in. obedience to one of the 

* XXII. LeQon D'Anat. Comp. 

f An Inquiry into the Uses of the Omentum, by James Rush, Philad. 1809. 



HISTOLOGY OF SEROUS MEMBRANES. 25 

general laws of the system, whereby the cellular substance beneath 
the serous membranes is disposed to secrete fat as the individual ad- 
vances in life ; which is exemplified on the heart and in the pleura. 
Another argument is, that in the ruminating animals, where there are 
four stomachs, and from the vegetable nature of their aliment these 
stomachs must, in the course of digestion, be very much distended, 
the great omentum is of proportionate magnitude.* 

As occurs in other parts of the body, also, the fat of the omen- 
tum accumulates in animals that take but little exercise, while it is 
very deficient in such as lead an active life. 

There is reason to believe, that the hard knots felt in the abdomen 
of such persons as suffer from abdominal affections, frequently de- 
pend upon the accumulations of the omentum majus at particular 
but variable points. 

SECT. III. — HISTOLOGY OF THE SEROUS MEMBRANES. 

As the peritoneum presents one of the best examples of a nume- 
rous class of membranes, called Serous, it will be useful at this point 
to inquire into their general condition and properties. They are, 
for the most part, thin, and strongly resemble compressed cellular 
membrane ; having been, indeed, by some anatomists, considered as 
such. They invariably assume the form of perfect sacs, and as they 
are found in all parts of the body, they are kept distinct from each 
other. The arachnoid membrane of the brain, the pericardium, the 
pleura, the synovial membranes of the joints, the bursas mucosas of 
tendons, the peritoneum, and the tunica vaginalis testis, belong to 
this class. They are not all of the same thickness, as some are 
much more dense than others ; they adhere to neighbouring parts by 
a lamina of cellular substance, which is also of variable thickness 
and ductility ; indeed, on some occasions, it is not entirely distinct, 
from its extreme shortness and tenuity. 

As the serous membranes are only displayed over the surface of 
the organs which they cover, after the manner of a double night- 
cap drawn over the head; their cavity always remains entire, not- 
withstanding it is variously modified by the shape of the organs 
protruded into it ; and has its parietes in contact, owing to external 
compression. They are entirely distinct from the essential struc- 
ture of the organs covered, and are displayed over those of the most 

* Cuvier, XXII. Le<;on. loc. cit. 



26 



ORGANS OF DIGESTION. 



dissimilar functions, as, for example, the intestines and the liver. 
A sac of this description, then, is of infinite importance in establish- 
ing between organs which border upon one another a strong par- 
tition ; and, consequently in warding off any injurious influence 
which their dissimilar natures would otherwise cause them to have 
upon each other. Important organs are, therefore, invariably thus 
insulated, so that whether in a healthy or in a diseased state, their 
actions are carried on within themselves ; and not only so, but it is 
even possible, and, indeed, is found in morbid dissections, every day, 
that an organ may be diseased while its serous covering is unaf- 
fected ; or the reverse. Thus, we have large suppurations in the 
liver, while its peritoneal coat is healthy ; large accumulations of 
water in the tunica vaginalis testis, while the testicle itself is sound ; 
in the thorax, with sound lungs and heart ; in the abdomen, with 
viscera generally sound ; in the joints, without an affection of the 
bones. Nothing is more common than to see partial adhesions, the 
result of inflammation, causing the opposite sides of these sacs to 
adhere, without any evident constitutional or visceral derangement ; 
and some of our plans of cure, as in the hydrocele, are founded 
upon this well established fact. 

The serous membranes are throughout thin, transparent, and 
white : in some points their tenuity is so extreme that they seem to 
consist simply in a smooth, polished surface, spread over parts ; this 
is strikingly the case on the interior face of the dura mater, on the 
ventricles of the brain, and on the cartilages of the joints. The 
evidence of their extension there, is consequently derived principally 
from induction; and from morbid alteration, in which they become 
thickened. Their internal surface in a natural state, is always 
smooth, highly polished, shining ; and, being also lubricated by its 
peculiar unctuous secretion, the opposite parietes, when they come 
into contact, glide freely upon each other ; a circumstance indispen- 
sable to the free action of the joints, and to the peristaltic motion of 
the bowels. Bordeu has asserted, that these remarkable characters 
of the serous membranes depend upon the compression and the 
friction to which they are continually exposed : but to this opinion the 
argument of Bichat is unanswerable, that in their earliest observable 
period in the fcetus they have the same polish. 

The fluid secreted from the serous membranes resembles, strongly, 
the serosity of the blood. It is poured out continually by the exha- 
lant orifices, and in a short time afterwards, is taken up by the ab- 



HISTOLOGY OF SEKOUS MEMBRANES. 27 

sorbents ; so that in a natural state there is seldom more than suffi- 
cient to lubricate the surface of the membrane. When the abdomen 
of an animal, recently killed, is exposed to the air, this fluid rises in 
the form of a vapour. The several experiments, as the application 
of heat, mineral acids, and so on, which prove the abundance of 
albumen in the serum of the blood, produce the same results when 
applied to the secretion from the serous membranes. 

The system of serous membranes has been considered by Bichat 
and others, as only a modification of cellular membrane, for the 
following reasons. The inflation of air into the cellular tissue sub- 
jacent to them, reduces them to the form of cellular substance. 
Protracted maceration produces the same effects with more certainty 
and precision. When cellular membrane is inflated, the parietes of 
the distended cells resemble strongly the finest parts of the serous 
system, as the arachnoid membrane. There is an identity of func- 
tions and of affections, for they are both continually engaged in the 
great work of exhalation and absorption, and suffer in the same way 
from dropsical effusion, with the only difference that the latter is more 
amassed in the one than in the other. My own experience goes to 
prove, that dropsy very seldom manifests itself, to any extent, in the 
cellular tissue without also going to the serous cavities, and the re- 
verse. The serous membranes are also of a uniform texture, like 
cellular substance ; and present no appearance of a fibrous matter. 

The serous membranes are furnished with a great abundance of 
exhalant pores, and of absorbents, which carry on their functions 
with great activity. They, when healthy, receive only the colour- 
less part of the blood, whence the uniform transparency of these 
membranes. The existence of exhalant pores, is proved by stran- 
gulating a piece of intestine with a ligature for thirty-six or forty- 
eight hours, when they become evident, by dilating themselves so 
as to receive red blood. A fine coloured injection produces the 
same result ; and also moistens, by the escape of its watery particles, 
the surface of the intestine, by a very fine halitus or dew. The 
intestine of a living animal, if wiped perfectly dry, will, after the 
same way, soon present another coat of serosity on its surface. The 
existence of absorbents to a great extent in them, may also be equally 
well proved, as they very readily receive a mercurial injection, which 
diffuses itself over their whole surface, and causes them to have the 
appearance of being formed entirely of such vessels. The readi- 
ness with which fluid effused into their cavities is taken up, is another 



28 



ORGANS OF DIGESTION. 



proof of the same. Bichat once saw them distended with air in a 
man who had become emphysematous from poisoning. Mascagni 
has frequently found them distended with the fluid of dropsical col- 
lections, which he recognised by its colour. It happened to the 
same anatomist to find in two bodies, where there had been an ef- 
fusion of blood into the thorax, the absorbents of the lungs gorged 
with blood. This faculty of absorption may sometimes be proved 
to continue for some hours after death, by keeping an animal in a 
warm bath. Mascagni asserts, that he has witnessed its continuance 
for fifteen, thirty, and even for forty-eight hours ; it is not improba- 
ble, however, that there was some illusion in these instances. 

In a preparation made by myself of the peritoneal coat of the 
stomach, pores giving this membrane a cribriform condition are very 
visible ; and Dr. Leidy, to whom I am indebted for a drawing of the 
same, has the facility of detecting, by the naked eye, similar pores 
over the whole peritoneum. Whether these pores are exhalant or 
absorbent, I have not yet ascertained.* They, by their uniformity 
and smoothness, bear every indication of being organized pores. 
If a similar arrangement exist every where over the entire extent 
of serous membranes, it is not an unreasonable conjecture to con- 
sider them as absorbing orifices, and thus to explain, the high 
absorbent powers of such membranes. These orifices are most 
probably formed by meshes of lymphatics ; as upon the mucous sur- 
face of the gastro-intestinal mucous membrane, the Follicles of 
Lieberkuhn, or the gastro-enteric follicles, are formed by meshes of 
veins. As serous membranes are also furnished with their Epithe- 
lium, hence, when it is raised by insufflation, the air does not 
escape through these pores. 

It is more than probable that the serous membranes are entirely 
deprived of red blood vessels ; the latter unquestionably exist, in 
great numbers, on the exterior surface, where they creep through 
the cellular substance, but they may be removed with a scalpel 
without affecting the continuity of these membranes. Again, where 
these membranes are free and unconnected on both surfaces, as in 
some parts of the tunica arachnoidea, there is no appearance of red 
blood vessels. In hernial protrusions, where there is a considerable 
prolapse of peritoneum, the blood vessels which are found abundantly 
about the neck of the sac do not follow out the course of the protrusion. 
Unquestionably some communication exists between the arterial sys- 
* See Plate, article, Stomach. 



HISTOLOGY OF SEROUS MEMBRANES. 29 

tern and the serous membranes, as proved by exhalation and morbid 
phenomena, but the mode is not well ascertained. We learn, how- 
ever, upon the authority of Miiller,* that there are some preparations 
of the peritoneum by Bleuland at Utrechty — and some also by Der 
Kolk, of the same membrane, which prove indubitably that this 
membrane contains vessels. 

In common hernia and in dropsy, the serous membranes become 
more thick : from my dissections I am inclined to think, that this 
change is not so great as is generally allowed ; for most frequently, 
by a careful removal of the exterior Cellular substance, they have 
been restored to their primitive condition. In other cases, as in 
large umbilical herniae, they are so much attenuated as to be found 
with difficulty. 

The power of extension which these membranes possess, is strik- 
ingly marked in dropsical effusions, in the development of tumours, 
and in pregnancy ; but much of this apparent quality is derived from 
their mode of attachment to adjacent parts, whereby they are drawn 
from one surface to cover another. This happens daily where the 
peritoneum is drawn from the lower part of the abdomen to cover 
the bladder in the distentions of the latter; in pregnancy, where it 
is drawn upon the growing uterus from all the neighbouring parts ; 
and in the distentions of the stomach by food or flatus, where it is 
drawn up from the omenta. The serous membranes have also a 
power of contraction equal to that of their extension ; but it should 
not be confounded with that condition where they are simply restored 
by the connecting cellular substance, to the surfaces to which they 
originally belonged. 

The sensibility of the serous membranes, is extremely obscure in 
a natural state, and only affords an imperfect sensation of touch. 
This is proved by the impunity with which they may be irritated on 
living animals. This has generally been attributed to the want of 
nerves, which however have been lately traced into the pia mater 
and arachnoid by Purkinje and Rainy — and into the peritoneum and 
pleura by Bougery. But, when the condition of inflammation is once 
established, they feel the most acute and distressing pain. Though 
they resist most frequently, and for a long time, disease in adjacent 
parts, yet it not unfrequently is extended to them at last. In such 
cases, it is generally a local instead of a universal affection, which 

* Physiol, p. 226. 
Vol. II.— 4 



m 



ORGANS OF DIGESTION. 



is communicated to them : Thus, in the cancer and scirrhus of the 
uterus; in disease of the spleen, and so on; the portion of perito- 
neum nearest the affected organ manifests the marks of the disease 
by preternatural adhesions and by disorganization, without the whole 
membrane being involved. 

As the serous system consists in many species of sacs, so each of 
them has some peculiarity of organization, of attachment, and of vital 
properties, which is stated elsewhere in the account of the species 
themselves. 

By acting on the inner surface of a bivalve shell with dilute acid 
a very thin pellicle is raised of a structure so uniform and so destitute 
of organic arrangement that it resembles more the walls of a soap 
bubble, and it is hence defined as being amorphous or structureless. 
In some parts of the human body the same exists, in others it is 
modified by being granular, and in others again by being covered with 
epithelial scales. This membrane, wherever found, has been desig- 
nated by Messrs. Bowman and Goodsir as a basement or primary 
membrane, and is supposed by them to be the matrix of the epithelial 
scales, which are successively evolved from its free surface, if it does 
not itself undergo a constant disintegration and renewal. The peri- 
toneum with all other serous cavities is considered to be lined by 
such basement membrane in some one of the conditions indicated. 

The microscope has thus proved that notwithstanding the extremely 
polished surface of the free side of the serous membranes, yet they 
are covered by an epithelium, which epithelium has been found on 
all except the sub-cutaneous bursee. Reichert indeed has described 
an epithelium upon the interior surface of the tendinous and of the 
subcutaneous bursee, like that of the arteries and of the true serous 
membranes.* The epithelium of the serous cavities is, like the epi- 
dermis, formed of flattened scale-like cells, which are, for the most 
part, polygonal or tesselated, like a pavement made of hexagonal 
bricks, and have each a nucleus in their centre. Some of these cells 
are furnished at their edges with minute hair-like filaments called 
cilia, which, during life and for some time after death, are in a state 
of continual whirling or vibration, and as is supposed, for the pur- 
pose of preventing a stagnation of the fluids in contact with them. 
These cilia are especially numerous and active in the ventricles of 
the brain. In some places the epithelium is found without the serous 

* Muller, Arch. 1814. 



THE STOMACH. 31 

membrane beneath, hence it is inferred that the latter is not so essen- 
tial as the former in the character of such membranes. 

These epithelia being always in contact with fluids, they differ 
from the cuticle by being pliant and humid ; but are restored with 
equal facility when they are lost by abrasion or inflammation. 



CHAPTER IV. 
Of the Chylopoictic Viscera. 

SECT. I. — OF THE STOMACH. * 

The Stomach (Ventriculus, Stomachus) is a hollow viscus situ- 
ated in the epigastric region, intended to receive at one end alimen- 
tary matters from the oesophagus, and to transmit them, at its other 
extremity, after digestion, into the intestinal tube, where the nutri- 
tious part of the food is absorbed into the circulation. It is a co- 
noidal sac, curved considerably upwards, and presents two Faces, 
two Orifices, two Curvatures, and two Extremities. 

The Faces of the stomach are, from their position, named ante- 
rior and posterior, or, one presents to the linea alba and the other 
towards the spine. The flat configuration is rendered more obvious 
when the organ is empty; for when distended it is rounded, and 
the anterior face is caused to look forwards and upwards from the 
resistance of the spine behind, while the posterior is of course in an 
opposite direction. In other respects they do not present any thing 
worthy of particular attention.! 

The two Orifices of the stomach are named Cardia and Pylorus. 
The first or Cardia is at the left and most superior part, but removed 
to the distance of two inches or more from the left extremity. It 
is generally considered a smooth uninterrupted continuation of the 
oesophagus into the stomach, immediately after the oesophagus has 
passed through the diaphragm into the abdomen. But in a prepara- 
tion, of this organ, made by drying,:}: and now in the anatomical 

* Anat. Atlas, Fig. 303 to 309, inclusive. 

f In some cases the posterior face of the stomach is concave to accommodate 
it to the spine . this is best seen on inflation and drying-. 
X December, 1828. 



32 ORGANS OF DIGESTION. 

cabinet, a circular rounded pad is very perceptible at the cardiac 
orifice ; being elevated two lines or more all around, so that it makes 
a perfect ring of from eight to twelve lines broad at its base. This 
pad seems to be composed of a cellular substance, which is almost 
perfectly white, elastic, and consists of the finest filaments, resem- 
bling carded cotton : it is placed between the lining membrane of 
the cardiac orifice and the adjoining coat. 

The Pylorus, when viewed externally, looks like a smooth con- 
tinuation of the stomach into the duodenum ; but when felt, there 
is a manifest thickening of the part, depending upon a structure to 
be presently explained. It points upwards and to the left side, 
but is, by the whole thickness of the liver, lower down than the 
cardia. 

The two Curvatures are designated the great and small, or the 
upper and the lower. The first, forming the upper margin of the 
stomach, is bounded at its extremities by the orifices, and is very 
concave ; its curvature is maintained both by a natural configuration 
and by the small omentum. The great curvature forms the whole 
inferior periphery of the organ, extending also from one orifice to 
the other. When the stomach is flattened, these curvatures form 
very evident boundaries to the anterior and the posterior face. 

The Extremities of this organ are remarkably different in size. 
That to the left forms the base of the cone, or the large extremity, 
and projects considerably beyond the cardia towards the spleen. 
It is a rounded cul-de-sac, or tuberosity, the dimensions of which 
will, of course, vary according to the state of distention. The right 
extremity, on the contrary, is produced by a gradual diminution of 
the organ from its middle to the duodenum. When the stomach 
has approached within an inch or two of the latter, it suffers a sort 
of constriction, which gives to the right end a more cylindrical shape. 
This part is sometimes called the Little cul-de-sac, or the Antrum 
pylori. 

When the stomach has been kept empty for some time previous to 
death, it is found not much larger than an intestine ; its variable 
magnitude, therefore, prevents any very rigid rule of dimensions 
from being applied to it ; most commonly, however, we find it be- 
tween the capaciousness of a pint and of a quart measure. 

It is retained in its situation by its continuity with the oesophagus 
and duodenum ; also by the hepatico-gastric, and the gastro-splenic 
omentum. It is in contact above, at its lesser curvature, with the 



THE STOMACH. 33 

diaphragm, the left lobe of the liver, and the lobulus Spigelii ; at its 
great extremity with the spleen, at its posterior face with the pan- 
creas, and at its greater curvature, with the colon and the mesocolon. 

The stomach is formed by four Coats or laminae, of a character 
essentially differing from each other : The Peritoneal, the Muscular, 
the Nervous, and the Mucous. 

The Peritoneal Coat envelops the stomach completely, and ad- 
heres closely, except at the curvatures, where, as has been men- 
tioned, a provision is made for the distention of the organ, by the 
looseness and the separability of the attachment of the two laminae 
of the omentum minus and of the majus. An uncovered space will, 
consequently, be found between the laminae at these places, along 
which the vessels run that furnish the stomach. The peritoneal coat 
is very thin, and is attached to the subjacent muscular, by very fine 
cellular substance, which permits it to be raised from the muscular 
by a careful dissection. In a dried preparation which I made,* 
there is an exhibition of minute foramina of the peritoneal coat, in 
apposition nearly as close as the follicles of the mucous coat. Already 
alluded to in the article on serous membranes, the attending plate, 
the drawing for which was made by Dr. Leidy from nature, exhibits 
well the appearance of the piece. 

The Muscular Coat is intermediate in thick- 
ness to that of the intestines and of the oeso- 
phagus, but its fibres are pale, are collected 
into flattened fasciculi, and go in three direc- 
tions. The most superficial are a continua- 
tion of the longitudinal fibres of the oesopha- 
gus, and are less numerous and less uniform 
in their distribution than the circular fibres. 
The greater part of them forms a flattened Organized pores in 
broad fasciculus, which extends along the Serous coat of Stomach 

lesser curvature of the stomach, from the car- from the ! ' 40 t0 the ! ' 8 

>,. ,, , . . r . ,, . . . of a line in diameter, by 

diac to the pyloric orifice. A thinner and less 

1 J nature. 

distinct fasciculus may be traced over the great 

cul-de-sac, and somewhat indistinctly, along the greater curvature ; 

* In 1839. 

4* 



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^V^ ^» ©** -°* * n 


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*" !at ::'<^ s *.# t ** <^*;3ffl 










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« ..'63 -; 


*»*<».*•■»' » "* «* OT *«•»$ 






, •» > '» 









34 



ORGANS OF DIGESTION. 



and a few others may be seen on the anterior and posterior faces of 
the stomaeh forming rather a fine linear or striated appearance than 
a perfect lamina ; this linear appearance is well exhibited by an 
oblique reflection of light from it. The second series consists in a 
lamina of circular fibres distinctly covering the whole surface of the 
organ. They are not so numerous near the cardia, but become more 
abundant as they are examined towards the pylorus, in the vicinity 
of which they are multiplied so as to form a lamina of two lines or 
more in thickness. The circular fibres are parallel with each other, 
and, when the stomach is much distended, their fasciculi separate so 
as to leave interstices between them in many places. The indi- 
vidual fibres do not surround entirely the stomach, but are rather 
segments of circles. The third and deepest series of fibres, consti- 
tuting the muscle of Gavard, from their discoverer, may be called 
oblique, and are arranged into two broad flattened fasciculi, one of 
which is placed to the left side of the cardia, and is prolonged over 
the anterior and the posterior face of the stomach ; while the other, 
being to the right of the same orifice, is extended over the anterior 
and the posterior face of the cul-de-sac, where it supplies the want 
of transverse or circular fibres : this series may be considered as a 
continuation of the circular fibres of the oesophagus. 

The Nervous or Cellular Coat (Tunica Propria,) connects the 
muscular with the mucous. It is formed by a compact, thick, and 
short cellular substance, which when inflated and dried, looks like 
carded cotton. It contributes much to the general strength of the 
organ, and serves to conduct the blood vessels and the nerves to the 
mucous coat. 

The Mucous or Villous Coat is the most internal, is not quite a 
line in thickness, and can be readily raised up by dissection. In 
an undistended state of the stomach it is arranged into a number of 
wrinkles, which are very irregular in their form, size, and direction, 
but disappear immediately on distention, or at least leave but very 
faint traces. It is continuous with the internal membrane of the 
oesophagus and duodenum, but presents a surface differing from 
either of them, and which is rendered very apparent by floating it 
in water. The epidermis, which is continued along the internal 
face of the oesophagus, ceases as mentioned around the cardiac ori- 
fice, and, by a slight maceration maybe raised. up and demonstrated 



THE STOMACH. 35 

to terminate there. An epithelium under modified circumstances is 
then found to start and to cover the entire interior of the stomach, 
and to be continued over the intestinal canal from one end to the other. 

It is softer, thinner, and more spongy than the common epidermis 
of the pharynx and oesophagus, but may be proved to exist by the 
microscope, by the exfoliations in scales found in the faeces, and 
also by insufflation, when it will be raised and may be dried in that 
state. 

This mucous membrane or coat, the office of which is to secrete 
the gastric juice for the digestion of articles of food, presents a sur- 
face that resembles very much common velvet, from whence the term 
villous is applied to it. If it be perfectly healthy, and the individual 
died suddenly a few hours after eating — it is found of a uniform light 
pink colour, without blotches or anything of extravasation under it. 
This fact I have had several opportunities of verifying, by experi- 
ment and by autopsies :* And more lately in the person of a crimi- 
nal, Williams, executed for murder. f It is usual, to find it, if ex- 
amined a short time after death, having, particularly along the smaller 
curvature and at the great end, a pink and sometimes a deeper 
colour, produced by an accumulation of blood in its veins. 

The texture of this membrane is soft, loose, and easily lacerated. 
When floated, in water and' examined with a magnifying glass, it is 
found to have a superficial honey-comb arrangement, and to be 
studded with a multitude of small follicles or orifices whose number 
is above fourteen thousand to the square inch, and whose diameter 
varies from the fortieth to the eighth of a line. In the vicinity of the 
cardiac and of the pyloric orifice, the same arrangement is more ob- 
vious, and exhibits also some small glands, which are more or less 
apparent, and called the glands of Brunner, being by some con- 
sidered muciparous and by others as the source of the gastric fluid.:]: 

At the junction of the lesser extremity of the stomach with the 
duodenum, the internal membrane is thrown into a circular dupli- 
cature constituting the Pyloric valve, and abridging the size of the 
orifice. It is seen most favourably in the distended and dried state, 
and then presents a sort of septum not unlike the form of the iris. 
Around the external periphery of this ring, the circular muscular 
fibres have an abrupt augmentation of number, which gives them, 

* See Amer. Journal Med. Sciences,. Vol. i. 1827. Horner's Pathol. Anat„. 
p. 195, &c. 

f Aug. 9, 1839. % Anat. Atlas, Fig. 311.. 



36 



ORGANS OF DIGESTION. 



when viewed from the duodenum, the appearance of a distinct cir- 
cular muscle, occasionally called the muscle of the pylorus, but it 
does not exist in a state so separate as this name indicates. The 
opening of the pyloric valve is generally circular, but sometimes 
ovoidal, and it is sometimes to one side. 

It is very common to find the stomach divided as it were into 
two compartments, by a contraction of its middle, resembling that 
of an hour glass. It is said that this occurs habitually during diges- 
tion ; in my personal observations, however, I have seen the stomach 
more frequently in this state when it contained nothing, not even air, 
than when articles of aliment were in it. 



Fig-. 22. 




The stomach is extremely vascular. Its arteries, being branches 
of the Cceliac ; are the Gastric, the Right, and the Left Gastro- 
Epiploic, and the Vasa Brevia. The first 
goes along its lesser curvature, the second 
and the third along its greater curvature, 
and the last, from four to six in number, go 
to its great cul-de-sac. They all approach 
it between the laminae of its omenta, and 
undergo many divisions and subdivisions 
in the cellular coat ; they at length termi- 
nate by forming a very fine and delicate 
vascular arrangement in the substance of 
the mucous membrane, and when success- 
fully injected give to the latter a thorough 
tinge of red. The veins follow the course 
of the arteries, and like them have frequent 
anastomoses, but are larger ; they terminate 
either directly or indirectly in the trunk 
of the Vena Portarum. The attending 
plate drawn by Dr. Leidy from an injection of mine, exhibits the veins 
of the stomach as seen with a microscope, on the mucous coat. 

The nerves of the stomach come from the Par Vagum, and from 
the semi-lunar ganglions of the Sympathetics. 

Its lymphatics arise from both the external and the internal sur- 
face, and their trunks having to pass first of all to the lymphatic 
glands situated along the curvatures, afterwards empty into the tho- 
racic duct. 



Reticulararrangement of 
veins to form the months 
of the mucous follicles of 
the stomach . Natural d ia- 
meter of meshes from the 
1-40 to the 1-8 of a line in 
diameter. 



INTESTINAL CANAL. 37 



SECT. II. — OF THE INTESTINAL CANAL. 

The Intestinal Canal is from thirty to thirty-five feet in length, 
and extends from the pylorus to the anus. Owing principally to a 
well marked difference in magnitude, it is divided by anatomists 
into the Small and into the Large intestine. 



' Of the Small Intestine* 

The Small Intestine [Tntestinum Tenue) commences at the pylorus, 
and terminates in the right iliac region by a lateral aperture into the 
large intestine. It is four-fifths of the length of the whole canal, 
and measures from twenty-four to twenty-eight feet.f When mo- 
derately distended its diameter is about one inch. It retains from 
one end to the other an uninterrupted cylindrical shape, with the 
exception that if the two ends be compared, the upper will be found 
larger than what is stated as the medium measurement, and the 
lower smaller; by which arrangement it occurs that the intestine de- 
creases successively from above downwards; and, as a whole, is 
slightly conoidal or spindle shape, though this diminution is so 
gradual that it is not perceptible in any short space. 

The small Intestine, like the stomach, consists of four distinct 
coats, the peritoneal, the muscular, the cellular, and mucous. 

The Peritoneal Coat is complete, and forms the external surface. 
It is continued afterwards in two laminae from the intestine to the 
lumbar vertebras, thereby constituting the Mesentery. The two 
laminee, where they depart from the intestine, are loosely connected 
with each other, for the purpose of allowing room for the dilatation 
of the intestine, on the same principle which is exemplified in regard 
to the stomach. 

* Anat. Atlas, Figs. 313 to 324, inclusive. 

f This is the generally received opinion of anatomists : it would appear, 
however, to be applicable only when the intestine is left attached to the me- 
sentery; for if it be cut off and straightened, it will measure thirty-four feet, 
which, added to eight feet of large intestine treated in the same way, will 
amount in all to forty-two feet. If to the estimate of this length we add what 
is lost by the doublings of the mucous coat, the entire length of surface must 
amount to nearly sixty feet ; at least, in many subjects. 



38 ORGANS OF DIGESTION. 

The Muscular Coat is next to the peritoneal. Its fibres are pale, 
and form a lamina not so thick as common writing paper. The 
superficial ones are longitudinal, not very distinct, and too much 
separated to form a perfect coat: they are most abundant on the 
anterior semicircumference or the one most distant from the Mesen- 
tery. The others all run in a circular direction, approaching to the 
spiral, and are sufficiently numerous to form a perfect coat: none of 
them perform a complete circuit of the intestine, but are rather 
segments of circles. This coat is united to the peritoneal by a thin 
scattered cellular substance. 

The Cellular Coat of the small intestine, {Tunica propria) also 
called the Nervous, like that of the stomach, is only a lamina of 
dense cellular substance, which serves as a medium of connexion 
between the muscular and the mucous coat: and also conducts to 
the latter the blood vessels, nerves, and lacteals. When inflated 
and dried, it puts on a beautiful cotton-like appearance — just as the 
corresponding coat of other parts of the alimentary canal does under 
the same treatment. 

In the lion this membrane presents a most elegant clear tendi- 
nous appearance, and is so strong that it will bear, from the interior, 
the pressure of a column of water eighteen feet high. The mus- 
cular and peritoneal coats splitting open, while it remains entire. 
Under this strong pressure of water neither the lacteals nor blood 
vessels are filled with it, which goes to prove that the introduction 
of articles into them, from the intestinal cavity, is a vital and not a 
physical action. 

The Mucous Coat is the most internal, and when it has been 
cleaned by maceration, exhibits an opaque pearly colour. It is 
remarkable for having its extent very considerably augmented 
beyond that of the other coats, by being thrown into a great number 
of permanent folds, or duplicatures; which lie one upon another 
successively, like the shingles upon the roof of a house. These 
duplicatures are the Valvulse Conniventes, and are for the most part 
about three lines in breadth. They are either placed in the direc- 
tion of the circumference of the intestine, or are very slightly ob- 
lique ; generally they go all around, but many of them are segments 
of circles, and by being arranged successively, their ends pass one 
another, or are connected by slight elevations. They are more 



INTESTINAL CANAL. 39 

numerous and broad in the upper than in the lower half of the in- 
testinum tenue, and are evidently intended to retard the progress 
downwards of alimentary matter, and to increase the surface for 
absorption and for exhalation. 

The mucous membrane, on the side which it presents to the cavity 
of the intestine, is furnished with a great number of delicate cylin- 
drical projections, resembling the down on the skin of an unripe 
peach, and called Villi,* from whence the term villous has also been 
applied to this coat. These villi are to be found in abundance every- 
where ; but in the upper half of the intestinum tenue they are so 
numerous as to stud its whole surface, and to be in contact with 
each other. They are from one-fourth of, to a line in length; and 
some of them, when examined with a microscope, appear flattened 
and fungiform. According to the estimate of Meckel, f where they 
are thickest, every square inch of intestine furnishes about four 
thousand of them, and by extending this computation, with a proper 
allowance for diminished numbers below, their aggregate amount is 
about one million.^ 

Each Villus is composed of an artery, a vein, and a lacteal ab- 
sorbent ; all united by cellular substance. § From the extreme vas- 
cularity of the mucous membrane, the blood vessels readily receive 
a fine injection and thereby become evident, forming a very delicate 
vascular net- work in each of the villi. It is generally believed, that 
the absorbent opens on its surface, but whether by one or more 
orifices is yet unsettled. According to the celebrated Lieberkuhn, 
there is commonly but one orifice at the end of each villus, and very 
rarely two: this assertion he considered himself as having esta- 
blished by passing a current of air through the villus till it was dried, 
and then slitting it open. Hewson, Cruikshank, and W. Hunter, 
on the contrary, are said to have found many more, amounting even 
to twenty, on such villi as were gorged with chyle. The subject 
has been fruitful in controversy to anatomists, and ranks many dis- 

* This is intended merely as an expression of the common and received 
notion, my own views are exhibited in the minute anatomy of this coat. — 
•Sect. hi. 

f Manuel d'Anat. 

X This is probably much below their real number; in an observation at the 
University we have found the villi on the ileum at its lower part amounting to 
six thousand four hundred to the square inch, but as their shape varies very 
much, as we shall see ; a rule cannot be derived from their shape. 

§ Anat. Atlas, Figs. 310—312. 



40 ORGANS OF DIGESTION. 

tinguished champions on each side ; but from the minuteness of the 
parts under discussion, it is exposed to much fallacy and illusion ; 
and is not as yet fully settled. The more important fact, however, 
is conceded by the admission of all, that there is a branch of the 
absorbent system in every villus; and which has, for its function, 
the absorption of chyle from the cavity of the intestine. 

A more recent observation has been made by Professor Krause,* 
in the body of a young man who had been hung after taking a full 
meal, he found the villi of the jejunum beautifully filled with chyle. 
The lacteal of each villosity arose by several branches, of which some 
terminated by a free extremity, and others by anastomosis with each 
other. Judging from his plate, he does not appearto have traced any 
branch to the surface of the villus. Muller says, that he himself had 
never seen any opening at the extremity of the villi. This corresponds 
with my own experience, as I have, also, in one case, had a fine op- 
portunity of seeing them distended with chyle. The villi, however, 
under any circumstances, cannot be considered as the sole organs 
for the absorption of chyle, for in many animals they do not exist. f 
A more calm inquiry into this matter will, probably, bring us all to 
the conclusion, that the villi exercise a tactile more than an absorb- 
ing power, which office their strong analogy with the papilla? of the 
cutis vera strongly points out. 

An abundance of Mucous Glands is found deposited in the cel- 
lular coat of the small intestine, between the muscular and the vil- 
lous ; their ducts open upon the internal surface of the latter, in the 
interstices of the villi, and from their smallness require the intestine 
to be floated in water, and examined with a magnifying glass, before 
they can be recognised. In order to see the glands themselves, the 
intestine must be cleaned by soaking it in water; it is then to be slit 
open longitudinally, and held between the eye and the light, in 
which case the glands appear like little points or spots in the thick- 
ness of the intestine. They are more abundant in the beginning of 
the latter, decrease about its middle, and increase again towards its 
termination. Their structure is very simple, as they consist in a 
congeries of blood vessels, terminating in short canals secreting 
mucus. I 

Some of these glands are microscopical, and are called cryptse : 

* Miiller's Archives, 1837. 

f Muller, Physiol, pp. 287, 288. 

£ Soemmering, de Corp. Hum. Fabrica. 



INTESTINAL CANAL. 41 

they appear as extremely fine cul-de-sacs, or blind pouches, made 
by inflections simply of the mucous coat, and are at the rate of near 
twenty-five thousand to the square inch, with a diameter varying 
from about the fortieth to the twentieth of a line. Other glands are 
to be found from that size to a line in diameter, and flattened. They 
are either alone or in clusters. The solitary ones (Glandules Soli- 
taries, Brunneri,) are found principally about the duodenum and 
the neighbouring portion of the small intestine, but also exist all the 
way down in a scattered manner. The others ( Glandules Jigminatcs, 
Peyeri y ) exist principally in the lower part of the small intestine, and 
are collected into clusters varying from a few lines to three or four 
inches in length, but seldom more than from eight to twelve lines 
broad. They are, for the most part, in elliptical patches, which, in 
a healthy state, may be recognised rather by a slight discoloration, 
than by the more ordinary means, and are generally situated some 
distance from the mesentery. There are about thirty of these clus- 
ters, of all sizes, in the ileum, and they are placed nearer and nearer 
to one another, in approaching the ileo-colic junction. All of these 
glands of Peyer are too much flattened to project sensibly into the 
cavity of the intestine, and, when they do, there is reason to believe 
that they are in a diseased state, at least in the adult. For the most 
part, in children, the glands of Brunner may be seen without diffi- 
culty, in the whole length of the small intestine, and in adults some 
are found to project like little hemispherical grains at wide intervals 
apart into the duodenum. 

The mucous coat of the small intestine is every where extremely 
vascular. 

The Small Intestine, though an uninterrupted tube from one end 
to the other, is divided by anatomists into Duodenum, Jejunum, and 
Ileum. There is some reason for the first name, but the two latter 
may be very conveniently blended, as has been done by some, under 
the term Mesenteric Portion of the intestinal canal. 

The Duodenum, named from its being about twelve inches, or 
twelve fingers' breadth in length, is nearest to the stomach, and is 
the commencement of the canal. It is considerably larger than 
either of the others, and is, moreover, susceptible of great dilatation, 
whence it has also been called Ventriculus Succenturiatus. Its di- 
rection is much varied ; beginning at the pylorus, it first of all passes 

Vol. II.— 5 



42 ORGANS OF DIGESTION. 

upwards and to the right side till it reaches the neck of the gall- 
bladder ; it then turns downwards, so as to form a right angle with 
itself, and descends in front of the right kidney to the third lumbar 
vertebra, being there placed behind the superior lamina of the trans- 
verse mesocolon. It then forms a round elbow, crosses the spine 
obliquely, under the junction of the mesentery and mesocolon, in 
ascending from right to left ; and making its appearance to the left 
of the second lumbar vertebra, is there continued into the mesenteric 
portion of intestine. 

The beginning of the duodenum is moveable, and has a peritoneal 
coat continued from the lesser omentum ; the descending and the 
transverse portions have no proper peritoneal coat, but are only 
loosely fixed between the laminae of the mesocolon ; the termination 
of the duodenum is both moveable and has a peritoneal covering, 
from being at the commencement of the mesentery. 

From the course assigned to the duodenum, it is evident that it 
forms the segment of a circle, the concavity of which looks to the 
left side. This concavity is occupied by the head of the pancreas. 
The transverse portion crosses the spine below the pancreas, and is 
separated from it by the superior mesenteric artery and by the vena 
portarum : behind it are the crura of the diaphragm, the ascending 
cava, and the aorta. 

The organization of the duodenum is the same with that of other 
portions of the intestinum tenue. Its peculiarities consist only 
in a partial deficiency of peritoneal coat, and in its augmented 
size. Its internal or mucous coat is very much tinged with bile, 
abounds in valvule conniventes, especially in its inferior three-fourths, 
and about four inches from the pylorus is marked by a small tubercle 
or elevation indicative of the common orifice of the biliary and pan- 
creatic ducts. The Glands of Brunn, commonly called of Brunner, 
are very conspicuous in this intestine on raising its mucous coat, 
and are so numerous near the pyloric orifice, as to form with some a. 
perfect layer, and to give it a granulated appearance for two inches 
or more. These glands originally called the Secondary Pancreas 
by Brunn, are also considered by Mr. Cruveilhier and Boehm to be 
pancreatic in their structure. This idea was first inculcated by 
their discoverer,* who considered them to secrete a peculiar liquor, 

* J. Conrad, A. Brunn, Gland. Duodeni Seu Pancreat. Secund. Descriptio 
Anat., for which treatise in full see Mangetus, Theatr. Anat. t. i. p. 276; 
Geneva, 1716. The other glands of Brunner found all the way down the small 



INTESTINAL CANAL. 43 

but thought that the action of the pancreas if it were exterminated 
would easily pass to them,* hence his appellation to them of Pancreas 
Secundarius. 

The Jejunum and Ileum form the remaining length of the small 
intestine, and have no external marks of difference from each other. 
They are strung along the mesentery, and, in consequence of their 
great length, are thrown into folds or convolutions, which give to 
them a complicated appearance. There is, however, no difficulty in 
tracing them regularly from one end to the other. They occupy the 
umbilical, the hypogastric, and a part of the iliac regions, and are 
surrounded by the circuit of the colon. The upper two-fifths is the 
jejunum, and the lower three-fifths, the ileum. This distinction, 
originally introduced by Galen, f from a supposition that the jeju- 
num was more frequently found empty than any other intestine, has 
no rigid anatomical support. The only difference between the two 
is, that the valvulae conniventes, existing as they do in the whole 
length of the jejunum, become less abundant at the upper part of 
the ileum, and finally disappear entirely towards its lower extremity. 
They decrease indeed very sensibly at the lower part of the jeju- 
num, and sometimes there are none at all in the ileum. In an ob- 
servation made carefully on this matter by detaching the intestine 
from the mesentery — inverting it and then measuring, I found the 
valvulse conniventes to cease as near as may be, in the middle of 
the length of the mesenteric portion of the intestinal canal. The 
above distinction into jejunum and ileum has been rejected by the 
most approved modern authorities, such as Haller, Soemmering, and 
Meckel. 

It sometimes happens, that the intestinum tenue has one or more 
blind pouches like cseca appended to its sides and opening into its 
cavity. 

The small intestine is supplied with blood from the superior me- 
senteric artery. Its nerves come from the sympathetic. 

The Mesentery (Mesenterium) is a process of peritoneum which 
serves, as mentioned, to connect the intestinum tenue to the poste- 
rior parietes of the abdomen, and extends its connexions from the 
left side of the second lumbar vertebra to the right iliac fossa. This 
attachment, called the root, is about six inches in length ; whereas, 

intestine, are evidently different from these in being more spherical, always 
solitary, and small in comparison. 

* Id. p. 291. f Portal, Anat. Med. 



44 



ORGANS OF DIGESTION. 



its lower circumference, which encloses the small intestine by giving 
it a peritoneal coat, is, of course, the whole length of the bowel, 
(duodenum excepted,) and, consequently, from twenty-three to 
twenty-seven feet in length. This expansion becomes intelligible 
the moment that the arrangement of the part is inspected, and is 
somewhat after the manner of a ruffle, except that it is not puckered 
at the root. 

The two laminae of peritoneum which form the mesentery, con- 
tain between them the superior mesenteric artery, and the correspond- 
ing portion of the superior mesenteric vein ; an abundance of lym- 
phatic or lacteal glands and vessels; ramifications from the solar 
plexus of the sympathetic nerves ; and a considerable quantity of 
cellular and of adipose tissue. The superior lamina is continued 
directly into the mesocolon, and at the place of junction the trans- 
verse part of the duodenum is very perceptible beneath. The lower 
lamina descends along the posterior parietes of the abdomen, con- 
cealing the large blood vessels there, and the ureters. 



Of the Large Intestine* 

The Large Intestine (Intestinum Crassum) receives the effete 
matter from the small, and is supposed also to make some peculiar 
secretion of fecal matter from its internal surface. It exceeds much 
in its diameter the small intestine, and differs also from it in not 
being by any means so nearly cylindrical. It commences at the in- 
ferior end of the small intestine, and terminates at the anus, de- 
scribing in this course, as mentioned, a circle which surrounds two- 
thirds of the abdomen, and embraces the intestinum tenue. Like 
the latter, though only a continuous tube, it is divided into three 
parts ; the commencement of it, which is below the insertion of the 
ileum, and about two inches in length, is the Ccecum, or Caput Coli ; 
the remaining portion, which occupies almost its whole length, is 
called the Colon, until it reaches the brim of the pelvis, when the 
name is converted into Rectum. 

The Mesocolon is a reflection or duplication of peritoneum that 
fixes the large intestine to the posterior parietes of the abdomen. 

Anat. Atlas, Figs. 325 to 331, inclusive. 



INTESTINAL CANAL. 45 

This duplicature is not of a breadth so uniform as the mesentery, 
but allows to the middle of the large intestine very considerable 
motion, up and down, according to the distention of the stomach, 
while the lateral portions are very much confined. For instance, in 
the right iliac fossa the mesocolon is so short that the posterior sur- 
face of the gut is in contact with the iliac fascia, and adheres to it by 
loose cellular substance ; and in the right and left lumbar regions 
the bowel is immoveably fixed in front of the kidneys near their 
outer margin : but in the space between these two points, that is to 
say, w T here the bowel traverses the hypochondriac and the epigastric 
or umbilical region, the peritoneal attachment, here called, from its 
situation, the transverse mesocolon, is so long and so loose that it 
forms a complete and moveable septum between the small intestine 
and the stomach. In the left iliac region, again, the large intestine, 
after having been bound down to the left lumbar, is suddenly 
loosened by an increased breadth of the mesocolon, which permits 
it to form a large convolution, called its sigmoid flexure. The me- 
socolon is then continued into the pelvis in front of the sacrum, first 
of all a little to the left of the middle line of the latter, and, as it de- 
scends it gets directly in front of the middle line. The portion of it 
in the pelvis is called mesorectum, from the gut which it serves to 
attach. 

The composition of the mesocolon is precisely the same with that 
of the mesentery, though it be not so thick : it, therefore, consists 
in two laminae of peritoneum, which contain between them some 
adipose and cellular matter, along with the arteries, the veins, the 
nerves, and the absorbent vessels and glands belonging to the large 
intestine. 

When the large intestine is inflated, it is rendered very obvious 
that it decreases in size from, its commencement to the lower part of 
the sigmoid flexure,, it then increases again in size just above the 
anus. Its surface is arranged into three series or longitudinal rows 
of projections, separated by transverse depressions, the whole cor- 
responding with an internal cellular arrangement, by the latter sur- 
face being the reverse of the former. 

Its coats, like the small intestine, are four in number; the perito- 
neal, the muscular,. the cellular, and the mucous. 

The Peritoneal Coat prevails in its whole extent, with the ex- 

5?- 



46 ORGANS OF DIGESTION. 

ception of the lower part of the rectum : on the ascending and the 
descending portions of the colon, however, where the latter comes 
in contact with the parietes of the abdomen, the peritoneum does 
not invest it entirely ; but the transverse portion or the arch, as it 
is called, and the sigmoid flexure, are completely surrounded. 

The surface of this intestine is studded with small projections of 
various lengths, called Appendices Epiploicse, which are small du- 
plicatures of the peritoneal coat containing fat. 

The Muscular Coat is thin, and like that of the small intestine, 
consists of two orders of fibres, the longitudinal, and the transverse 
or circular. 

The longitudinal fibres have the peculiarity of being collected 
into three equidistant, flattened fasciculi or bands, of about half an 
inch in breadth, which begin by a common point at the extremity 
of the ccecum, and extend to the upper end of the rectum. One 
of them is along the line of junction with the mesocolon, another 
anterior, and the third inferior. These fibres, being shorter than 
the other coats of the gut, have the effect of puckering them into 
the internal cellular condition alluded to ; for, when they are cut 
through, the intestine is much elongated, and its cells disappear. 
It occasionally happens that the longitudinal fibres, instead of being 
confined to the bands mentioned,, exist in considerable quantity over 
the intermediate spaces; in this case the cellular arrangement is not 
so complete, and in some instances is entirely dispensed with ; of 
the latter, an example is in the Anatomical Museum. 

The circular muscular fibres form a thin semi-transparent lamina 
beneath the last, and do not present any peculiarity of interest, they 
make a thicker layer than exists in the small intestine. 

The Cellular Coat, or Tunica Propria, is a thin lamina of dense 
cellular substance, serving to connect the muscular with the mucous 
coat, and to conduct the blood vessels and nerves to their termina- 
tions on the latter. 

The Mucous Coat lines smoothly the internal face of the cellular, 
and has no doublings or folds, exclusively in it, like the valvulae 
conniventes of the small intestine.* The transverse projections 

* This may be considered as the general rule: if the gut be examined, 
however, in its whole length, here and there narrow folds may be found in 
some subjects.. 



INTESTINAL CANAL. 47 

which it makes between the longitudinal bands, into the cavity of 
the gut, and which separate the cells of the large intestine from each 
other, are not mere duplicatures of it alone, but are also constituted 
by the other coats. 

Near its commencement this coat has the fungous appearance of 
the stomach, but about the sigmoid flexure it has a plain, smooth, 
and, to a degree, a polished surface. It has but few villi, such as 
exist in the small intestine ; indeed, some anatomists deny that it 
has any, and I have not myself seen them after repeated and care- 
ful examinations. Its muciparous glands are numerous, and, when 
somewhat enlarged, project ; they are very conspicuous about the 
sigmoid flexure, and in the rectum. The enteric follicles exist in this 
large intestine strikingly, as they do in the mucous coat of the sto- 
mach and small intestine. Their number, on an average, is about 
twenty thousand to the square inch, with a diameter varying from 
about the fortieth to the twentieth of a line. When examined with 
a microscope they make this mucous membrane, owing to its smooth- 
ness, look like a riddle. The lacteals are not abundant. 

The mucous coat of the large intestine is very vascular, but not 
so much so as that of the small intestine. 

Each division of the large intestine has some peculiarities of 
structure and connexions ; which may now be attended to. 

The Coecum, or Caput Coli, is generally from an inch and a 
half to two inches long, has a rounded termination below and 
somewhat to the left, from which proceeds an intestinal process, 
the Appendicula Vermiformis. The latter is from three to four 
inches long, is cylindrical, has a diameter of two or three lines, and 
consists of the same number of coats, having the same structure 
with other portions of the intestinal canal ; its base is the place from 
which the three longitudinal bands start. It is attached to a narrow 
duplicature of peritoneum, a process of the mesentery, which per- 
mits it to float loosely in the abdomen. It seldom contains faeces, 
but is kept distended by flatus. 

The coecum, as mentioned, is, for the most part, confined to the 
right iliac fossa, but we very frequently see it with a length of peri- 
toneal attachment permitting it to descend for a short distance into 
the lesser pelvis. 

The Ileo-colic Valve (Valvula Bauhini) is formed at the junction 
of the ileum with the caput coli. This valve, destined to prevent 



48 ORGANS OF DIGESTION. 

the return of fcecal matter from the large into the small intestine, con- 
sists in a transverse elliptical opening, or slit, whose two lips become 
approximated in the distentions of the colon. The ileum runs into 
the left wall of the large intestine, and continues its cellular and 
mucous coats into the corresponding coats of the latter. The cir- 
cular fibres of the large intestine separate to a certain degree to 
permit this introduction, but their farther separation is restrained at 
each commissure or corner of the lips, by a blending of the structure, 
aided by a few ligamentous fibres, designated as the retinacula of 
Bauhin or of Morgagni ; which, however, are frequently not very 
distinct. This separation is also restrained by the two longitudinal 
bands between which the lips are placed, one of which bands is at 
the posterior commissure, and the other only a short distance from 
the anterior. The lips themselves, formed principally by the mucous 
membrane, approach one another after the manner of the ship dock 
or canal gate ; the superior is somewhat broader than the inferior. 
Their power, as well as their existence, depends entirely on the 
tension which is kept up by the natural connexions of the parts ; for 
a very slight dissection causes them to become almost effaced, and 
instead of forming an elliptical transverse opening, to be converted 
into a round patulous one. 

The Colon, properly speaking, has some regional distinctions 
which are serviceable to accurate description. The right lumbar 
colon, which is bordered in front by the small intestine, and behind, 
by the right kidney, extends from the ileo-colic valve, to the margin 
of the false ribs of the corresponding side. The transverse colon, 
bordered above by the stomach, and below by the small intestine, 
goes from one hypochondriac region to the other. It is generally 
found more distended than the other portions. The left lumbar 
colon descends from the hypochondriac region of the left side to the 
sigmoid flexure, being bordered behind and to its right margin by 
the left kidney, and in front by the small intestine. The sigmoid 
flexure, placed in the left iliac fossa, forms a convolution, but is very 
indifferently described by the term applied to it. It is occasionally 
very long and loose, and terminates at the left sacro-iliac symphysis. 
It is not unfrequently found destitute of the partitions which prevail 
in other parts. 

The Rectum begins at the left sacro-iliac symphysis, and passes 



INTESTINAL CANAL. 49 

obliquely downwards to the centre of the sacrum, thence in front of 
the middle line of the sacrum, and of the coccyx, to terminate at the 
point of the latter. It is not regularly cylindrical, but, just above 
the anus, is dilated into a wide pouch, flattened from before back- 
wards by the pressure of the bladder, and very distinguishable upon 
the introduction of the finger, for it is but seldom in a contracted 
state. It, of course, has a flexure by adapting itself to the concavity 
of the sacrum, and is bounded in front by the bladder, the prostate 
gland, and the vesicular seminales of the male ; and by the vagina 
and the uterus of the female. 

The peritoneum covers only the superior two-thirds of the rec- 
tum, and attaches it by the short duplicative, called the mesorectum, 
to the front of the sacrum. A small pouch, passing down between 
the vesiculse seminales almost to the base of the prostate, is formed, 
as mentioned previously, by the peritoneum in its course from the 
rectum to the bladder. 

The muscular coat of the rectum has a thickness and redness sur- 
passing much that of any other intestine, and is divided very clearly 
into two laminse, the external of which consists in longitudinal and 
the internal in circular fibres. The external forms in itself a com- 
plete coat continuous with the longitudinal bands of the colon, but 
is much increased in thickness over them by additional fibres. The 
circular fibres also form a complete coat, and, just below the pouch 
of the rectum, are multiplied so much for eight or ten lines as to be 
a perfect internal sphincter muscle, bearing a strong analogy with 
the pyloric muscle of the stomach.* At the anus, an arrangement 
of the muscular coat prevails, which is not sufficiently attended to 
by anatomists. The longitudinal fibres, having got to the lower 
margin of the internal sphincter, turn under this margin between it 
and the external sphincter, and then ascend upwards for an inch or 
two in contact with the mucous coat, or rather its cellular substra- 

* It has been recently asserted that there is also a sphincter muscle four 
inches above the anus, half an inch wide in front, and one inch wide behind, 
from whence according to Mr. Velpeau the fibres go in crossing one another to 
fix themselves to the front of the sacrum. Mr. Lisfranc appears to have first 
announced it and Mr. Nelaton to have described it. Malgaigne, Anat. Chi- 
rurg. vol. 2d, p. 343. Paris, 1838. I doubt very much the uniformity of the 
distinct existence of such a muscle, not having been able to find it in the dis- 
sections which I have instituted for the purpose, unless a portion of the ordi- 
nary circular fibres should have been selected for that designation, in which 
case several others may be said also to exist. 



50 ORGANS OF DIGESTION. 

turn, into which they are finally inserted by fasciculi which form the 
base of the columns of the rectum ; many of the fibres, however, 
terminate also between the fasciculi of the circular fibres. This 
connexion must have obviously much influence in the protrusions 
of the mucous coat, which take place in hemorrhoids and in pro- 
lapsus ani. 

The mucous coat of the rectum is thick, red, and fungous, and 
abounds in raucous lacunae and glands. It is smoothly laid above, 
but below it is thrown into superficial longitudinal folds called 
columns. At the lower ends of the wrinkles, between the columns, 
are small pouches of from two to four lines in depth, the orifices 
of which point upwards; they are occasionally the seat of disease, 
and produce, when enlarged, a painful itching. An original obser- 
vation of Dr. Physick, on the nature of this affection, and the remedy 
for which consists in slitting them open or removing them, induced 
me to look for the ordinary natural structure, which I have ascer- 
tained to be as now described.* The radiated wrinkling of the 
anus is from the influence of the external sphincter ani muscle. 

In some subjects, large cells are formed in the cavity of the rectum 
by transverse doublings of the mucous coat only, resembling the 
valvula? conniventes of the small intestine; this, however, is not 
the most frequent arrangement, though deserving of notice. It 
takes place under the following mechanism. About a finger's 
length from the anus there is a puckering of the gut, or deep wrink- 
ling, such as occurs in the colon, and it arises from a similar cause, 
that is, an abbreviation of the longitudinal layer of fibres of the gut: 
this abbreviation is not wholly circular, but occupies the semi-cir- 
cumference of the gut on one side, and then a little higher up, the 
semi-circumference of the other side. This shortening of the gut 
brings the fasciculi of its circular muscular fibres more together, 
and, therefore, accumulates them into a greater thickness. At a 
corresponding part on each side of the gut in its interior, exists a 
transverse doubling of the mucous coat forming the valvula con- 

* See an interesting paper on Fistula in ano, by M. Ribes, in Mem. de la 
Societe D'Emulation, vol. 9, 1826; where the influence of this structure is 
alluded to.— Also, an elaborate and excellent article by Dr. Reynell Coates, in 
the Cyclopaedia of Pract. Med. and Surgery, Philada. 1835, under the term Anus. 
It appears that Glisson and Ruysch first described them as valves. The ac- 
curate Winslow (Douglas' Translation vol. ii. p. 149, anno., 1749,) was also 
acquainted with this structure. 



INTESTINAL CANAL. 51 

nivens alluded to. The result of this arrangement is a semi-circular 
valve on each side, one above the other, the margins, or diameters 
of which pass each other in the empty and contracted state of the 
rectum, but touching at the same time, and they present an addi- 
tional barrier to the involuntary evacuation of fasces.* 

Most subjects, however, have the mucous coat without these 
valves, and merely in superficial wrinkles of various directions. 
The large intestine is supplied with blood from a part of the 

superior mesenteric artery, from the whole of the inferior mesenteric, 

and from the internal pudic. Its veins empty into the vena portarum. 

Its nerves are derived from the solar and the hypogastric plexus of 

the sympathetic. 



SECT. III. — ON THE MINUTE ANATOMY OF THE MUCOUS COAT 
OF THE ALIMENTARY CANAL.f 

In the preceding account of the mucous coat of the stomach and 
bowels, I have admitted the most generally received opinions as 
it is in every way proper for medical men (o be aware of them. 
Having been, however, much occupied, a few years ago, in ascer- 
taining the pathology of AsiatieJ cholera by dissections, the obser- 
vations which I then made upon the healthy and diseased structure, 
have induced me to modify very much my former views, as will be 
seen in the following pages; the subject has since then been taken 
up largely by the anatomists of Europe, with nearly similar results. 

The mucous coat of the alimentary canal, in a healthy state, 
and successfully injected, appears to consist almost entirely of a 
cribriform inteitexture of veins. These veins being commonly 

* It has latterly been advanced by Mr. O'Beirne, that in a natural state the 
rectum is empty, and that the accumulation of feces preparatory to a stool 
occurs in the sigmoid flexure of the colon, where they are retained by a con- 
traction of the upper end of the rectum. The principal ground of this opinion 
is, that fcecal matter is rarely met with in the rectum. The observation is so 
contradictory to my experience in the dissecting room and on patients, that I 
cannot but reject it, though it appears to be obtaining some currency, or at least 
is quoted respectfully. Journal Hebd. 1833, vol. xiii. p. 126. Malgaigne, 
Anat. Chir. vol. 2d, 341. 

f Anat. Atlas, Figs. 332 to 337, inclusive, the preparations by Dr. Horner 
represented by these figures are in the Anat. Museum. 

X Amer. Journ. Med. Sciences, Vol. xvi. May, 1835. 



52 ORGANS OF DIGESTION. 

empty at death present themselves then as a soft spongy structure, 
which gives rise to the ordinary description of its sensible condi- 
tion as a velvety layer. The most minute injection of the arteries 
scarcely makes itself visible among these veins, when they are pro. 
perly injected also; a straggling branch only here and there exhi- 
biting itself. The arborescence of the arteries is confined to a 
level beneath the venous intertexture, and is there developed to an 
extreme degree of minuteness, being intermixed with correspond- 
ing venous ramuscles, generally larger and more numerous than 
the arteries themselves. This arrangement seems to occur in that 
surface of the cellular coat, which makes the base or ground of the 
mucous. The fine venous trunks of this deeper layer have their 
originating extremities directed vertically towards the cavity of 
the gut, and by that means receive the blood of the first venous 
intertexture or layer, as the petrous sinuses join the cavernous, or 
the veins of the penis arise from its spongy structure. The meshes 
of the first venous intertexture are exceedingly minute, and vary 
in a characteristic manner in the stomach,* small intestine, and 
large. This intertexture is very different in its looks from a com- 
mon vascular anastomosis, and produces in the colon an appear- 
ance resembling a plate of metal pierced with round holes closely 
bordering upon each other ; these holes constitute, in fact, the fol- 
licles of Lieberkuhn, so called from their discoverer ;f these folli- 
cles are gaping orifices, the edges of which are rounded off, and 
their depth is that of the thickness of the venous anastomosis ; being 
bounded below by the arterio-venous layer, just alluded to, and by 
the cellular coat of the part. Nothing short of an entirely success- 
ful injection will exhibit this venous anastomosis as described ; and 
it may be seen either by injecting a vein, or an artery provided 
the injection passes from the arteries, into the veins, but the latter 
process is the least desirable, because we lose the benefit of a dis- 
tinction of colour between the two sets of vessels.^ 

* See fig. 332 to 335 inclusive. 

| De fabrica et actione Villor. intest. ten. Leyd., 1745. 

% The observations more recently of Dr. Gaddi of Modena, have resulted 
in witnessing a similar indisposition of the arteries to ramify in the mucous 
coat, and the almost exclusive prevalence of the venous vessels there. He 
has some views beside of a peculiar nature, such as that the extremities of the 
veins begin by open mouths on the cavity of the intestine, then unite to form 
a hollow sphere situated in the submucous tissue, and that the terminating 
ends of the arteries discharge into these spheres or vesicles. Brit. & For- 
Med. Rev. Oct., 1841, p. 530. 



ANATOMY OF THE MUCOUS COAT. 53 

Ordinary modes of examination give no evidence of the existence 
in the alimentary canal, from the cardiac orifice of the stomach 
to near the anus, of an epidermis or epithelium; on the contrary, 
they rather lead to a belief of its being absent, in consequence of the 
softness, tenuity, and transparency of the mucous membrane ; but 
that it is really present, may be proved by the following process: — 
Tear off' the peritoneal coat from a piece of small intestine — invert 
the part and inflate it to an emphysematous condition; the epithe- 
lium will then be raised as a very thin pellicle, and may be dried 
in that state ; but as this pellicle retains the air, we hence infer that 
it lines the follicles, and is uninterrupted by any perforations. This 
epithelium, if the part be previously injected perfectly, shows dots 
of injecting matter like those left in the rete mucosum upon a mi- 
nute injection of the skin ; but no arborescence of vessels if it be 
raised up from the veins, by the inflation stated. In so doing the 
villi disappear, are in fact unfolded. 

In addition to the above proof, the microscope in the hands of 
numerous modern observers now shows, according to the original 
opinion of Lieberkuhn, the existence of an epithelium over the 
whole alimentary canal, and which is formed of minute soft scales, 

Fig. 23. 




Cylinders of the intestinal epithelium, after Dr. Henle : — a. Cylinders 
from the cardiac region of the human stomach; b. the same from the jejunum; 
c. cylinders of the intestinal epithelium viewed by their free extremity ; d. 
ditto, as seen in a transverse section of a villosity. 

The villi cannot be seen to full advantage except they be erected 
by an injection, in which case those of the upper part of the small 
intestine are found to run into each other very much like the con- 
volutions of the cetebrum, and to press upon each other's sides in 
the same way. Some of them, however, are merely semi-oval 

Vol. II.— 6 



54 ORGANS OF DIGESTION. 

plates, the transverse diameter of which exceeds the length or ele- 
vation. At the lower end of the small intestine they become sim- 
ply conical projections, somewhat curved, with the edges bent in 
or concave, and they retain this mechanism until they entirely dis- 
appear near the ileo-colic valve. In the whole length of intestine 
there is, however, every variety of shape of villi, from oblong curved 
and serpentine ridges, to the laterally flattened cone standing on its 
base ; the first condition changing gradually to the last in the de- 
scent of the bowel. Conformably to this definition of villi, none 
exist either in the stomach or colon, for there we have only the 
venous mesh. The villi of the jejunum are about the thirtieth of 
an inch high, and those of the ileum about one-sixtieth. 

In the ileum, the superficial venous layer has great regularity and 
the conical villi stand out beautifully from its anastomoses, or in 
equivalent language, from the divisions of the follicles. In the 
upper part of the small intestine the follicles are in equal number 
to what they are in the ileum ; the regularity of their arrangements 
being interrupted by the long serpentine and oval villi ; but invaria- 
bly the same venous intertexture exists and forms, in both parts, the 
chief bulk of the villi, by passing into them. 

In the stomach the follicles vary much in size, and there is an 
arrangement whereby many of the smaller ones are seen to open into 
the larger : on an average about two hundred and twenty-fitfe are 
found upon every square of one eighth of an inch, which would give 
of course to an inch square sixty-four times that amount, or fourteen 
thousand four hundred follicles. Conceding the whole stomach to 
present an area of ninety inches, which is probably below the mark 
when this organ is moderately distended, as exhibited in the prepa- 
ration upon which this calculation is founded, the entire number of 
follicles is one million two hundred and ninety-six thousand. 

The great uniformity of size of these follicles in the colon, and 
its even surface, enable us to count them with more certainty, and 
they appear to exist at the beginning of this gut at the rate of about 
four hundred for every eighth of an inch square, but in the sigmoid 
flexure at the rate of about two hundred to the same area ; they be- 
come, in fact, both smaller and less numerous in descending towards 
the anus. Their average may be stated, therefore, as three hundred 
for every one-eighth of an inch square— and as nineteen thousand 
two hundred for every inch square. Admitting the entire area of 
the colon to be five hundred inches, and nineteen thousand two 



ANATOMY OE THE MUCOUS COAT. 00 

hundred of these follicles, to exist on every inch square, the aggre- 
gate number will be nine millions six hundred and twenty thousand. 

In the colon the resemblance is almost exact with what is called 
the perforated card or Bristol board, used by ladies for working em- 
broidery or variegated needle-work. 

Again, estimating the whole area of the mucous coat of the small 
intestine at fourteen hundred and forty inches, and allowing for in- 
terruptions occasioned by villi ; about three hundred and ninety fol- 
licles exist upon every one-eighth of an inch square, or 24,960 upon 
an inch: say then, that about twenty- five thousand follicles are found 
upon every square inch, and the two numbers multiplied, produce 
thirty-six millions. 

The entire number of follicles in the whole alimentary canal, is, 
by the preceding estimates, forty-six millions nine hundred thousand, 
and upwards. I am very far from pretending to have counted them 
all, but have made an approximation to the actual number by ob- 
serving sections of different portions of the same subject, and verify- 
ing the observations upon other subjects. 

The external surface of the cutis vera presents, as it were, in 
outline, the same follicular arrangement; the venous reticular inter- 
texture appearing broader, not quite so perfect, and more shallow, 
and forming the papillae ; but as additional experiments are wanting, 
it may be passed over with this transient notice ; perhaps, in- 
deed, a more skilful hand in adopting the hint may perfect the 
details.* 

In the stomach, the largest of these follicles is about one-ninety 
eighth of an inch in diameter, and the smallest about one-four hun- 
dred and ninetieth. In the colon the largest is about one-two hun- 
dred and forty-fifth of an inch in diameter, and the smallest about 
one-four hundred and ninetieth. In the small intestines their size 
varies in about the same ratio as in the colon, but thdy are much 
more irregular in shape, being scattered more in groups, in conse- 
quence of the villi intervening: some of them penetrate obliquely 
towards the foundations of the villi ; hence, w r hen examined from the 
exterior, their distribution is more regular, and they are seen lodged 
in the cellular coat of the gut. 

I have endeavoured to keep the estimate of the number of folli- 

* It is probably this which constitutes the bloody pimples (bourgeons 
sanguins) of the skin. 



56 ORGANS OF DIGESTION. 

cles below what other calculators would make it upon an observa- 
tion of my preparations, and a fair measurement of the area of the 
alimentary canal, lest the number may seem excessive and incredi- 
ble ; I have, therefore, the most reasonable assurance of being within 
bounds on that point. I may now ask their use ; is it to secrete or 
absorb ? If they are simply secernents of mucus, the number, one 
would think, much greater than so limited a secretion requires— 
moreover, why is it that they become smaller and less numerous 
towards the lower end of the large intestine, where greater lubri- 
cation is required for hardened faeces ; in addition, are not the glands 
ofBrunner, (solitarice,) and of Peyer, (agminata,) amply sufficient 
to furnish the required mucus? Again, after most sedulous obser- 
vations upon the villi of all kinds, finely erected by my injections, 
and placed under most accurate, simple, and compound micro- 
scopes, I find, invariably, a polished reflecting surface, uninterrupted 
by foramina, either at their ends or sides, while many of these fol- 
licles are found passing obliquely into their bases. An excellent 
Woollaston's doublet, which makes the villi of the ileum appear an 
inch long, exhibits them with a polished translucent surface, without 
foramina, except where a villus from accident has been broken, 
a contingency readily recognised by one in the habit of viewing 
them. Finally, if the lacteal foramina of Lieberkuhn and others, 
do really exist, why is it that the raising of the intestinal epidermis by 
inflation, does not exhibit these foramina by the air escaping through 
them, but, on the contrary, admits of a dried preparation in that 
state, the villi being completely effaced.* 

Taking into consideration these several objections to the theory 
of the follicles being secreting orifices, it appears to me that a better 
idea of their use is called for, which suggestion is submitted to the 
profession, with the hope that a more capable person will remove 
the difficulty, by additional confirmation of preceding theories, or 
by the invention of a new one ; for my own part, I am much inclined 
to adopt the opinion of their absorbing faculties. It is generally con- 
ceded that the erection and prehension of the Fallopian tube is pro- 
duced by a vascular turgescence, in which the veins, from their num- 
ber, must execute an important part ; in like manner, as these intes- 
tinal follicles are formed in the midst of veins, their orifices only be- 

* In these and other microscopical observations, I owe much to my friend, 
Dr. Paul Beck Goddard, now Professor of Anatomy in the Franklin Medical 
College of Philadelphia. 



ANATOMY OF THE MUCOUS COAT. 57 

come erect and patulous by the distention of those veins, and can- 
not be well seen by the eye alone, especially in the small intestine, 
unless an injection has succeeded fully; but the erection of these 
veins during digestion puts the follicles in a similar condition ; there 
is, therefore, some ground of inference, that the act of the Fallopian 
tube in conveying a germ, and of a follicle in conveying into the 
thickness of an intestine congenial matter, may be analogous. 

The follicles would seem at least not to be essential to the secre- 
tion of mucus, as it is found where the follicles do not exist; for ex- 
ample, in the frontal, maxillary and sphenoidal sinus, and also in 
the cavity of the tympanum. 

Notwithstanding the facility with which we can detect these folli- 
eles, I have failed entirely under various means of examination, in 
finding any orifices to Peyer's glands, in the dried intestine : they 
appear to be merely small lenticular excavations* in its substance, 
and wherever a cluster of them exists, it disturbs the arrangement 
of the villi, and gives to them a scattered unequal distribution. I 
would also suggest very respectfully to anatomists whether our know- 
ledge in regard to them is sufficiently exact to render farther inquiry 
useless ? for my own part it appears that this subject requires some 
additional attention. As they are found closed the probability is 
that their contents are discharged when required, by a regular dehis- 
cence. 

The above view, relative to the alimentary mucous membrane, 
presents at least a degree of novelty, by determining, with some pre- 
cision, the whole number of the Gastro-enteric Follicles of the human 
body, or Follicles of Lieberkuhn, and how they are in every instance 
formed by meshes of veins; while the arteries enter only inconsidera- 
bly into the composition of the same mucous membrane, to an 
amount in some measure comparable to the presence of the arteries 
in other erectile tissues, as the corpus spongiosum and cavernosum 
penis. In the latter it is familiar to every practised anatomist, that 
the branches of the arteries are but small, as they terminate in the 
cells of the penis, which are to be considered as only a modification 
of the incipient stage of venous trunks. If the corpus spongiosum 
were in fact spread out into a thin and single membrane, so as to line a 

* This observation has been confirmed in Germany by Boehm, who has 
come to the same conclusion. He says that they contain a white milky and 
rather thick fluid, with numerous round corpuscles of various sizes, but mostly 
smaller than blood globules. Am. Journ. Med. Sc. vol. xxi. p. 218. 

6* 



58 ORGANS OF DIGESTION. 

hollow viscus, it would present no very undue representation of what 
I have denominated the superficial venous layer of the ahmentary 
canal ; it being also admitted that within the circuit of every anas- 
tomosis, a follicle was formed. 

Viewed on the preparations of the mucous membrane of the small 
and large intestines which I have, these follicles appear like puncta 
lachrymalia disseminated by thousands over every inch square, and 
existing so invariably upon every part, that, as I have stated, the 
smallest calculation of their numbers puts them at from forty to fifty 
millions. 

It may be stated incidentally, that it is the whole of this vascular and 
follicular structure, endowed with vital actions the most important to 
life, and presenting in the aggregate an area of about thirteen square 
feet, the size of a small breakfast table ; whose morbid derangements 
constitute the essential features of Asiatic cholera.* It has been 
shown in some of my dissections, that this apparatus in the pro- 
gress of cholera is detached entirely from the stomach and colon, in 
consequence of the excessive actions going on in them. The small 
intestines also, in some of my preparations, exhibit in patches a 
similar phenomenon ; but as the entire observation has been pre- 
sented to me in its true light only since the disappearance of the 
disease, I have had no means of ascertaining the extent to which 
they suffer in this way. 

The anatomy of the muciparous, system of the alimentary canal 
unquestionably requires a more exact attention than is generally 
bestowed upon it, and especially so as to distinguish between 
that part which is really glandular, and the foramina or follicles now 
under consideration. The following extract will explain the diffi- 
culty which exists with some in regard to a proper conception of the 
latter. 

"The mucous glands, called also follicles or cryptse mucosae, are 
to the membranes of that name what the sebaceous follicles are to 
the skin ; that is to say, folds of the mucous membrane in form of 
a cul-de-sac, whose orifices open upon that membrane. These folli- 
cles have not yet been discovered over the whole surface of the mucous 
membrane; but here, as with the skin, analogy leads us to admit 
them. It is not long since they have been discovered in the pitui- 
tary membrane, where their existence had been denied. Be this as 

* For illustrative preparations by the author, see Wistar Museum, 



ANATOMY OF THE MUCOUS COAT. 59 

it may, we shall use the same observation upon these glands that 
was made on the sebaeeous, viz., the impossibility of making an 
exact dissection of the eapillary tissues does not allow us to discover 
all the forms of animal matter ; but wherever a particular humour is 
found in a tissue, we are forced to conclude that this latter is or- 
ganized in such a manner as to be able to produce it, and when in 
place of one humour we meet with many, we must acknowledge 
that the tissue is complex. Such is precisely the case with the mu- 
cous membrane of the digestive canal, and especially of the stomach, 
which could have a form of animal matter calculated to furnish di- 
gestive juices, although no gland destined to that purpose is dis- 
coverable."* 

In infancy, especially, the mucous glands have a sensible thick- 
ness, which enables us to see them, but the smallest of them require 
the aid of a microscope, and appear to have been described by 
Galeati. f As the paper is not to be had in any of the public libra- 
ries of this city, I can only quote from it on the current authority of 
anatomical works. In a note to the anatomy of the human body by 
Sir Charles Bell, article Intestine, it is stated as follows : — " It has 
been supposed that the fluids excreted from the surface of the intes- 
tines were furnished by very minute foramina, (whieh are visible by 
particular preparations,) in the interstices of the villi. See the letter 
of Malpighi to the Royal Society of London on the pores of the sto- 
mach, and the paper by M. Galeati in the Bologna Transactions, on 
the inner coat, which he calls, the cribriform coat. The pores, ac- 
cording to Galeati, are visible through the whole tract of the canal 
and particularly in the great intestines." Meckel designates these 
as glandular bodies under the name of glandules mucosa, cryptce mi- 
nima. Another order of glands are those of Brunner.| They are 
readily found in the duodenum at all ages ; and particularly well in 
infancy, as low down as the ileo-colic valve. The third order are 
the glands of Peyer, discovered in 1677. § The celebrated Ruysch 
appears also to have understood the existence of the follicles of the 
stomach, and Swammerdam to have had some idea of those of the 

* Broussais' Physiology. First American edition, p. 419'. 
f l)e cornea ventriculi et intestinorum tunica. Conim. Bonon., 1745. 
X Glandulae intestini duod-eni vel pancreas secundarius; discovered in 1715. 
See Mangetus, Theat. Anat. 
§ See also Mangetus for the description from Peyer. 



60 ORGANS OF DIGESTION. 

small intestines,* and he calls them tubuli glandulosi intestinorum in- 
teriors. I may here remark, that the figure of the villi of the small 
intestines given by Hedwig, in his Disquisit. Ampullarum, &c. 1797, 
and which appears, from its introduction into Caldani's and M. Jul. 
Cloquet's Anatomy, to have a classical value, is, judging from my 
own preparations, too much a work of the imagination, executed 
under probably some fallacious views of the part itself: a cluster of 
cylindrical villi, with holes at the ends, would be an anomaly, for 
those of the upper part of the intestines are either serpentine folds, as 
represented in my preparations, with branches running into contigu- 
ous folds ; or semi-oval laminae ; while those lower down are of a 
flattened conical shape, somewhat bent, but in every instance they 
are destitute of what has been termed by Lieberkuhn an ampulla, 
and to my eye as stated have uniformly polished surfaces, uninter- 
rupted by foramina. 

Mascagni has also introduced views of a good kind in regard to 
the follicular structure of the stomach and colon. f But it is to Sir 
Everard Home, that we are indebted for one of the best papers on 
the glandular structure of the stomach of different animals. | 

As the real muciparous glands have an orifice leading into each 
by the admission of anatomists, the follicles described commonly 
by them, are of this description, and are not comparable in number 
to the follicles found in the venous meshes. The highest estimate 
of the number of the former, as made by M. Lelut, fixes them at 
about forty-two thousand. § In consulting many of the distinguished 
modern authorities on this subject, there seems to be scarcely any 
thing in the anatomy of the intestinal canal which is presented in 
a more indefinite way; especially in regard to the small intestines, 
than the difference between the follicles, properly speaking, and the 
glands; and none of them, so far as I know, have previously to 
myself undertaken to approximate the entire number of the follicles 
and to point out how each one is the centre of a venous anasto- 
mosis, is formed by it, and always exhibits itself in a collapsed state 
when the vein is not turgid. || 

* Mangetus Theat. Anat. Vol. I. p. 310. 

f Prodromo delta grande anatomia. Tab. xiii. 

t Phil. Trans. 1807 and 1817; and also his Comparative Anatomy. 

§ Bouillaud, Traite du Cholera, p. 256. 

|| The anatomy of the Gastro-intestinal mucous membrane has elicited 



HISTOLOGY OF MUCOUS MEMBRANES. 61 

SECT. IV. — HISTOLOGY OF MUCOUS MEMBRANES. 

The extent of the mucous coat of the alimentary canal, and the 
important and varied sympathies which it has with most other parts 
of the body, render proper some remarks on membranes of this kind, 
generally. Mucous Membranes are so called from the nature of the 
secretion which they furnish: and the term having been first applied 
to the lining coat of the nose, a similitude of character has caused 
its extension to that of other organs. The celebrated Bichat, the 
founder of the science of general anatomy, was the first to adopt 
fully, and to perceive the value of this classification ; since which 
it has been almost universally received by anatomists. 

As the skin forms an external covering to the body, so mucous 
membrane lines the internal surface of the hollow viscera. When 
it is recollected that this membrane forms an internal tegument to 
the whole alimentary canal, from the mouth to the anus; to all the 
urinary and genital apparatus; to the whole respiratory system, from 
the nose down the trachea and throughout the lungs; it will be 
admitted that its extension exceeds much that of the skin. 

A mucous membrane presents two surfaces, one of which adheres 
to the contiguous parts, and the other is free by being internal. The 
adherent surface is attached by a cellular structure somewhat con- 
densed. This cellular structure is principally remarkable for its 
want of disposition to secrete fat into its interstices; a property of 
immense importance, as without it, obstructions would be con- 
tinually occurring to the destruction of life: it is pervaded by a 
multitude of fine vessels and nerves, running forward to be spent 
upon the mucous membrane ; and has been unfortunately named 
nervous coat, by anatomists of high authority. The strength of at- 

several good papers in Europe since 1835, inclusive, the period of my own 
publication, which was in anticipation of the others. In point of date they 
are rather confirmatory of preceding observations than distinguished by novel- 
ties, and the venous anastomosis does not seem to be understood or appreciated, 
except by Dr. Gaddi, of Modena, alluded to in a preceding note. In addition 
to the authorities already quoted, the reader may advantageously consult Boehm 
de Gland, Intest. Struct. Penit. Berol, 1835. Boyd on the Structure of the 
Mucous Membrane of the Stomach, Edinburgh, Med. and Surg. Journal, 1836. 
Likewise Recherches Anatorniques sur la Membrane Muqueuse, &c, par M. 
Natalis Guillot in L'Experience, p. 161. Paris, 1837-8, and Mailer's, Archives, 
1838 and 1839. 



62 HISTOLOGY OF MUCOUS MEMBRANE. 

tachment which it furnishes is somewhat varied ; for example, in the 
small intestinal canal I have often seen the mucous membrane caught 
at one end and entirely withdrawn from the muscular coat, an ex- 
periment which alone can give rigid ideas of its greater length, as 
by it all the duplicatures or valvulse conniventes are stretched out. 
The experiment succeeds much more certainly by the regular pres- 
sure of a column of water between the tunics of the intestine. The 
mucous membrane of most organs is arranged into wrinkles and 
duplicatures, for the purpose of augmenting its extent. This ar- 
rangement prevails in the nose, and, as mentioned, in the oesopha- 
gus, in the stomach and intestines; to say nothing of many other 
instances which are noticed in the description of each organ. In 
some examples, they are permanent, and, in others, depend on the 
state of contraction of an exterior muscular coat. The interior face 
of the mucous membranes, allowance being made for the inequali- 
ties just stated, moreover, presents, when closely viewed, an abun- 
dance of more minute depressions and of elevations, causing it to 
resemble velvet. Some of these depressions are so large as to give it 
a cellular appearance,* as in many parts of the intestinal canal, and 
in the gall-bladder, and have been particularly described by Sir 
Everard Home. 

In regard to organization, the mucous membranes are of a soft, 
spongy consistence ; easily yield to mechanical violence ; and de- 
pend for their strength upon the surrounding cellular coat. They 
are not of a uniform thickness ; for example, they are much thinner 
in the urinary and genital apparatus, than in the alimentary canal : 
they also present some varieties of consistence. They yield very 
readily to putrefaction, and are quickly reduced to a pulpy state 
by the action of the mineral acids. Caustics of all kinds act more 
promptly on them than on the skin, owing to the protection of the 
latter by a dry epidermis ; Bichat states, that in the practice of the 
Hotel Dieu, this effect is frequently exemplified, by the administra- 
tion of lunar caustic among the common people for the purpose of 
poisoning. The nitric acid leaving the silver, quickly applies itself 
to the mucous membrane of the stomach, and disorganizing it, 
forms a whitish eschar, which, if life be preserved long enough, is 
finally detached in a membranous form. 

* They are not to be confounded with the follicles, but are a miniature re- 
presentation of what is called tripe, in culinary language. 



HISTOLOGY OF MUCOUS MEMBRANES. 63 

One of the remarkable properties of the mucous surfaces of the 
stomach and intestines is, that of coagulating milk. According to 
the experiments of Spallanzani, the gastric juice, in the living state, 
assists in this change ; but it is perfectly well known in domestic 
affairs, that the dried stomach of a calf, where the juices have been 
completely evaporated, is also productive of it. The observations 
of the same author led him to conclude, that the peritoneal and 
the muscular tunics of the stomach are insufficient to produce this 
effect. 

The internal surface of the mucous membranes is furnished with 
small projecting points or spiculae, called papillae or villi. They 
are particularly conspicuous and numerous, as mentioned, on the 
upper surface of the tongue and in the small intestine, and bear an 
analogy of function and organization with the very fine papilla? 
which are seen invariably on the surface of the cutis vera. These 
papillae are constantly furnished with nervous filaments, giving 
them a high degree of sensibility ; and with an abundance of blood 
vessels. The term papillae has been more exclusively applied to 
the projections on the surface of the tongue, from their greater 
size ; they are there also more distinctly covered with an epidermis, 
frequently called epithelium, or periglottis. The villi, from their 
connexion with the process of digestion, have been emphatically 
denominated the roots of animals. According to M. Beclard,* 
who has examined them upon a plan of his own contrivance well 
suited to accurate microscopic observations, they are presented 
under a diversity of shapes. Those of the pyloric half of the sto- 
mach, and of the duodenum being broader than they are long, are 
composed of very small thin laminae, having a tufted arrangement. 
Those of the jejunum are long and narrow, having more the form 
commonly assigned to them, while in the lower part of the ileum 
and in the colon they again become laminated. 

It should be observed, that, notwithstanding the assertion of 
Leeuwenhoek, Hewson, Hunter, and others, the fact is still called in 
question, by many of the most distinguished anatomists of the 
present time, MM. Beclard, J. F. Meckel, Rudolphi, Muller, &c, 
whether the orifices of the lacteals are, under any circumstances, 
visible on the surface of the villi. Admitting that they do not open 

* Anat. Gen. p. 253. These notions are not, however, in unison with my 
own, as just stated. Sect. III. 



64 HISTOLOGY OF MUCOUS MEMBRANE. 

as stated, the power of interstitial absorption in the mucous mem- 
brane will still account for the chyle finally getting in the lacteals, as 
well as for fluids passing into the circulation from the stomach, when 
its continuity with the intestinal canal has been interrupted.* 

The Epidermis or Epithelium of mucous membranes is very dis- 
tinct at their external orifices, but becomes less and less apparent 
towards the interior of the body, until it finally cannot be distin- 
guished by the eye alone ; and anatomists of a former period generally 
considered that it is entirely deficient, notwithstanding the assertion 
of Haller to the contrary. It is a matter of common observation, 
that when the interior of mucous membranes is exposed by an ever- 
sion for a long time, to the action of the atmosphere; they take on 
more of the structure of skin, and become evidently covered with a 
cuticle which protects them and diminishes their secretion. This is 
exemplified in eversion of the vagina from prolapsed uterus, in elon- 
gated and tumid labia interna, and in other ways : restore the parts 
to their natural situation, and they are brought back to their original 
structure. In the partial prolapse of the mucous membrane of the 
rectum, from piles, corresponding circumstances occur. From this 
we infer, that the full development of cuticle depends very much 
upon the degree of exposure which any surface of the body has to 
undergo. The reverse also takes place: shut up or close any sur- 
face of the skin so that it is put in the condition of an interior cavity, 
and it immediately begins to assimilate itself to a mucous membrane. 
This is proved by the tendency in young children to a detachment 
of the cuticle, or excoriation of the opposed surfaces of the deep 
wrinkles about their thighs and in their perineum ; a tendency obvia- 
ted by the nursery practice of covering these surfaces with powdered 
starch. It is also manifested frequently in the dressing of wounds 
with sticking plaster, where an incautious approximation of the con- 
tiguous surfaces of the skin, not only is followed by excoriation, but 
even by ulceration. The existence of an epithelium every where on 
mucous membranes, now, is definitely settled by microscopical ob- 
servers, and has become one of the most established points of 
anatomy. This epithelium is formed by a continuous layer of cells 
not only in the gastro-intestinal mucous membrane, but in the va- 
rious prolongations of the latter into the ducts of the proximate glands 

* Should the suggestion of the absorbing powers of the gastroenteric fol- 
licles which I have proposed in Section third, be correct, it will dispose of the 
difficulties and opposing opinions alluded to in this paragraph. 



HISTOLOGY OF MUCOUS MEMBRANES. 



65 



and in fact a similar arrangement exists wherever a mucous mem- 
brane is found. These cells are according to some the emanation 
of an amorphous basement membrane, they execute the specific 
secretion of the part which they cover, and thus whatever may be 
the similitude of their structure, perform very varied offices. 

Varieties of Cells or Corpuscles forming the epithelium of Mucous 
Surfaces. From Henle. 



Fig. 24. 



Fig. 25. 





Fig. 24 — a, b, c, d, e, f. Nucleated ciliary cells ; their free end straight 
and furnished with filaments, called Cilia) of different shapes, a, Nucleus. 

a, Cilia. 

Fig. 25. — A row of ciliated cells, rounded at end. a, In a line with nuclei. 

b, Cilia. 

Fig. 26. — Cylindrical cells apart with their nuclei. 

Fig. 27. — Cylindrical cells grouped compactly, a, Bodies, b, Free extre- 
mities. 

The mucous membranes vary in colour from a very light pink to 
a deep red, which is owing to the blood that circulates in them. In 
cases of suffocation, they become almost brown from the congestion of 
blood in them, while in fainting they turn white from the desertion 
of the latter. The vessels after having penetrated the thickness of 
the membrane, ramify with extreme minuteness on its surface. The 
veins in an injection invariably predominate over the arteries by their 
greater size and distensibility. In consequence of their superficial 
situation, the vessels being unsupported on one side, are exposed to 
rupture from slight concussions ; in this way hemorrhage is produced 
in the lungs from coughing ; and bleeding at the nose from blows 
upon the head. 

Exhalant orifices exist in great numbers in the mucous membranes : 
this is especially the case in the lungs, where the pulmonary perspi- 
ration, as it is called, is very obvious to common observation. Else- 

Vol. II.— 7 



66 ORGANS OF DIGESTION. 

where, this discharge is so much blended with the mucus of the part, 
that it is difficult to appreciate its quantity. From the superficial 
situation of the blood vessels, it is clear that the exhalant orifices or 
pores, have but a short course to run. This is considered by Bichat 
as a satisfactory reason for the tendency of the blood to escape through 
them, or to ooze out where there is no rupture. 

Absorbents exist also in great numbers, as proved by the absorp- 
tion of chyle, of watery drinks from the intestinal canal, and by the 
inhalation of the vapour of spirits of turpentine into the lungs, rapidly 
communicating the particular smell of this article to the urine. There 
are, moreover, cases recorded of obstructed urethra, where the urine 
has been almost entirely absorbed by the mucous coat of the bladder. 

In regard to nerves, the mucous membranes are well furnished 
with them. Bichat has remarked that wherever these membranes 
are situated near the surface of the body and enjoy common sen- 
sibility, they are almost wholly furnished from the central portions 
of the nervous system, as the brain and spinal marrow : this is ex- 
emplified in the conjunctiva, the pituitary membrane, the palate, 
the glans penis, &c. On the contrary, the sympathetic nerve fur- 
nishes the intestines, the bladder, and the excretory tubes gene- 
rally. 

Mucous Glands, as they are called, exist throughout the system 
of mucous membranes, being situated either under them or in their 
thickness. From them is derived the mucilaginous fluid which 
lubricates so abundantly their interior surfaces, as to facilitate 
the passage of extraneous bodies, and, at the same time, to protect 
the membrane from mechanical violence. These glands are of 
various sizes, from that of the tonsils and the muciparous glands 
on the lips, cheeks, and root of the tongue, to the almost impercep- 
tible cryptae of the bladder and urethra. Their shape is either 
lenticular, rounded, or that of a pouch. The former two have 
their parietes of a sensible thickness, but the last are too thin to be 
distinguished from the mucous membrane itself. For the most part, 
the excretory duct of these glands is short and patulous, so as to 
lead directly into the substance of the gland. This is remarkably 
the case with the tonsils, which consist in a congeries of these fol- 
licles; and with the glands on the root of the tono-ue. In some 
animals they are so numerous as to form almost a distinct lamina to 
the intestines ; after the manner of the human subject, on the palate 
and parietes of the mouth. 



THE LIVER. 67 

The Mucosity discharged from these glands is one of the prin- 
ciples of animals, and, as is well known, exists also to a great 
extent in some vegetables. When perfectly pure and fluid, it is 
white, transparent, inodorous, and insipid. It is insoluble in alco- 
hol, but soluble in acids. Water forms more than nine-tenths of 
it, the remainder is mucus, properly speaking, blended with some 
neutral salts of soda and potash. 

The mucus which covers the surface of the mucous membranes 
consists chiefly of separated particles of epithelium mixed with a 
fluid exudation, while the mucous follicles are said to pour out a 
fluid holding mucous globules suspended. 

The mucous membranes are exposed to a multitude of morbid 
alterations, such as polypus, scirrhus, cancer, phlegmorrhagise or 
serous fluxes, blennorrhagise or mucous fluxes, inflammation in all 
its forms, gangrene, ulcerations, and congestions. 



CHAPTER V. 
Of the Assistant Chylopoietic Viscera. 

SECT. I. — OF THE LIVER.* 

The Liver (Hepar, Jecur) secretes the Bile, and is the largest 
glandular body in the human frame. It, as mentioned, occupies 
the whole of the right hypochondriac region, the upper half of the 
epigastric, and, as it becomes thinner in going towards the left side, 
it occupies a small space in the right superior part of the left hypo- 
chondriac region. Its whole superior face is in contact with the 
diaphragm; on the left it is bounded by the spleen, and below by 
the stomach, and the transverse colon ; behind it, are the vertebral 
column and the ascending cava. 

The shape of the liver is like one half of an ovoidal body cut 
into two in the direction of its long diameter, and having the thick 
end turned to the right side. It is about ten inches in length by 
six or seven wide, and weighs from four to five pounds in the 

* Anat. Atlas, Figs. 339 to 347, inclusive. 



68 ORGANS OF DIGESTION. 

adult. Its colour is a reddish brown, generally; though, on its 
under surface and about its edges, broad blue or black patches are 
constantly met with, which do not indicate any morbid derange- 
ment. 

Its upper surface is of an uniform convexity, rather more promi- 
nent at the right posterior part than elsewhere ; adjusts itself accu- 
rately into the concavity made by the under surface of the dia- 
phragm ; and is unequally divided from before backwards by the 
suspensory ligament. The anterior margin is thin, and is notched 
where the suspensory ligament begins ; the posterior margin is much 
thicker, and has near its middle a broad depression, to fit it to the 
projection of the vertebral column. The ascending vena cava 
forms a superficial sulcus upon this margin, and frequently there is a 
complete canal through the substance of the liver for transmitting 
it. The right extremity is very thick, and almost fills the hypochon- 
driac region of that side, while the left extremity is reduced to a 
thin, tapering, and flexible edge. 

The under surface of the liver is much more irregular than the 
upper; it is traversed in an antero-posterior direction, in a line cor- 
responding with the attachment above of the suspensory ligament, 
by the umbilical fissure, (Sulcus Umbilicalis) which extends from 
the notch in the front edge to the depression behind, and obtains its 
name from having accommodated in the fcetal state, the umbilical 
vein, now converted into a round ligamentous cord. In the poste- 
rior part of this fissure is likewise to be seen, in the same condition, 
what remains of the ductus venosus. The anterior portion of the 
umbilical fissure is not unfrequently converted into a complete canal, 
by a portion of hepatic substance crossing it like a small bridge. 
The transverse fissure (Sulcus Transversus, Intermedins) is situated 
in the middle of the under surface of the liver, and extends alonsr a 
third or fourth of the long diameter of the latter. It begins some- 
what to the left of the umbilical fissure, and crossing it at right angles, 
proceeds towards the right extremity. It contains the vena portarum, 
the hepatic artery, and the hepatic duct, lymphatics and nerves; all 
of which are bound to each other by a close cellular substance. 

The suspensory ligament above, and the umbilical fissure below, 
give occasion to divide the liver into Lobes, Right and Left ; of 
which the right is by much the largest, and accommodates almost 
entirely the transverse fissure, having also on its under surface some 



THE LIVER. 69 

subordinate elevations, to wit, the Lobulus Spigelii and the Lobulus 
Quartus, together with the G all-Bladder. 

The Lobulus Spigelii is placed between the transverse fissure and 
the posterior margin of the liver, to the right of the posterior end of 
the umbilical fissure. Its shape is somewhat prismatic, bifurcating 
in front ; one of the elongations or prongs is a papilla overhanging 
the transverse fissure, and is, therefore, considered as one side of the 
gate-way {porta) opened for the vena portarum ; the other elongation 
is a small ridge, sometimes called Lobulus Caudatus, and is lost 
gradually on the under surface of the great lobe, by inclining to the 
right. 

The Lobulus Quartus, or Anonymus, is not by any means so 
elevated as the last, but having a flattened surface, is placed in front 
of the transverse fissure, between the fore end of the umbilical fis- 
sure and the gall-bladder ; its posterior extremity is the other side 
of the gate-way (porta) of the Liver, and is just opposite to that fur- 
nished by the Lobulus Spigelii. 

The liver, from being completely enveloped in peritoneum, has 
a smooth glossy appearance. The reflections of this membrane, 
from it to ihe parietes of the abdomen, form the ligaments, as they 
are called, which consist each of two laminae. The Falciform Liga- 
ment, or Suspensory, containing in its anterior margin the remains 
of the umbilical vein, now called Ligamentum Teres, begins at the 
umbilicus, extends from it along the linea alba and the middle line 
of the diaphragm, and, as mentioned, is reflected to the upper sur- 
face of the liver, from the anterior to the posterior margin. The 
Right Lateral Ligament is situated behind, and departs from the back 
part of the diaphragm to the posterior margin of the right lobe. The 
Left Lateral Ligament also goes from the back part of the diaphragm, 
and is attached along the posterior margin of the left lobe. Where 
the suspensory ligament inclines on each side into the lateral, it 
passes with so much obliquity as to leave some portion of the poste- 
rior margin of the liver uncovered by peritoneum ; the latter, where 
it describes the periphery of this space, has been rather unnecessarily 
designated as the Coronary Ligament. 

In addition to the peritoneal coat, the liver has another, connect- 
ing it with the peritoneum, and seeming to be only condensed cellular 
substance, which also penetrates into the substance of the gland, and 
holds its constituent parts together. It is particularly well seer., 
within the circle of the coronary ligament. 

7* 



70 ORGANS OF DIGESTION. 



Of the Organization of the Liver. 

The glandular substance of the Liver is fragile and easily lace- 
rated ; and consists of a congeries of spheroidal or polyhedrical 
grains, called by Malpighi acini from their resemblance to small 
berries ; they are best seen on tearing the organ, are united in mass 
by the elongations of the cellular coat, and traversed by the trunks 
of the blood vessels. Each of these granulations is about the size 
of a millet seed, and is a representative of the entire gland, as its 
structure is complete in itself; being formed by the capillary termi- 
nations of the blood vessels, and by the origins of a branch of the 
hepatic duct, called the porus biliarus. 

The liver is made extremely vascular by the ramifications of three 
kinds of blood vessels, the Vena Portarum, the Hepatic Artery, and 
the Hepatic Veins. The first two convey the blood to it, and the 
third removes it again, into the general circulation, by emptying into 
the ascending vena cava. There are also the commencing radicles 
of the Hepatic duct; the Lymphatic vessels; and the Nerves. 

When examined with a microscope, the acini are seen to be made 
of smaller graniform bodies, and also present under particular cir- 
cumstances two colours, a brown and a yellow. This difference of 
colours, observed originally by Ferrein,* gave occasion to the division 
of the substance of each acinus into Cortical (Substantia corticalis, 
brunnea,) and into Medullary, (Substantia medullaris, flava) the pro- 
priety of which is, however, not fully sanctioned even at the present 
day. The Cortical or brown matter is the investment of the other, 
and depends for its colour, principally upon the great proportion of 
capillary vessels, derived from the three orders, the vena portse, 
arteria hepatica, and venae hepaticce. The Medullary or yellow 
matter, is the place of origin of the biliary ducts, and is supposed to 
derive its colour from the presence of bile in their radicles. f The 
ground ofthis distinction is so unsatisfactory and it seems to depend 
so much upon some contingent condition of the circulation of the 
blood, that while it is admitted by very eminent authority, as Bichat 
and J. F. Meckel, it is as earnestly rejected by equally high, as 

* Mem. de Paris 17o5, Hist. 51. 

f The application cf these terms has been changed, as Ferrein called the 
brown matter the Medullary, ajad the yellow, die Cortteal. 



THE LIVER. 71 

Portal and E. H. Weber. My own observations have been such as 
to incline me to the authority of the two latter. 

Some new microscopic details have been attached to the account 
of the Liver within a few years, by Purkinje and Henle, and are 
fully confirmed by Wagner and others. 

The proper hepatic structure, the parenchyma of the liver, it 
would thus seem is composed in the case of each acinus, of a collec- 
tion of epithelial cells, so near together as to have their shape 
moulded by mutual contact, and to become polyhedrical. They 
are about the 1-7000 of a line in diameter, and have a nucleus of 
about the fourth or fifth of that size. Hallman has placed these 
structures at a much smaller size, about one-tenth of the diameters 
stated : and Wagner makes them much larger, amounting in fact to 
1-100 of a line. There are other measurements of an intermediate 
kind, showing all together that there are great diversities in their 
real magnitude.* These cells have their shape varied from a 
flattened spheroidal to a quadrangular or pentangular one, and con- 
tain within them a yellow bilious looking material, having intermixed 
with it several globules of fat large and small. The biliary matter 
contained in them is concluded to be proof sufficient of these cells 
being the real agents of the secretion of bile. The essential features 
of this process then consists in the successive evolution of these cells, 
of their active elaboration of the bile — of their rupture or dehiscence 
and of the further conveyence of the bile into the pori biliarii, by a 
process as yet not fully understood. The existence of these hepatic 
cells is easily ascertained: by tearing a liver especially a young one, 
and then scraping it, they turn out so abundantly that allowance 
made for the blood vessels, and cellular or areolar tissue, they seem 
to compose it almost wholly. 

The idea of Huschke in regard to their connexion with the pori 
biliarii is, that the bile is elaborated in their central nucleus, as 
proved by nitric acid, and that an extremely attenuated branch of a 
bile duct 1-684 of a line in diameter, reaches each cell, being attached 
to it like a pedicle, and in that way receives the discharge of bile. He 
believes that the fat of the hepatic cell or vesicle, seen also upon its 
surface, is converted into bile. This view of the terminal points of the 
biliary ducts is very much a repetition of the penicillous structure of 
former anatomists, its arrangement being perhaps more attenuated 
than any they had an idea of. He says that to the present moment 

* Huschke Traite de Splanchnologie, p. 123. 



72 ORGANS OF DIGESTION. 

he has never witnessed the reticulated connexion of the fine extremi- 
ties of the bile ducts in their origin from the acini, which are repre- 
sented in the ideal figure of Mr. Kiernan. Also that he has not 
found the anastomoses of the larger bile ducts, said to have been 
discovered by the latter, in the left hepatic ligament; and he has been 
equally unsuccessful in detecting the communications said by Berres 
to be, between the blood-vessels and the biliary ducts. 

My own injections of the liver, considered by good judges as 
very successful and not inferior in that respect to some upon which 
a new anatomy of the liver has been founded, exhibit a very high 
vascularity upon the periphery and in the intervals of the acini; this 
vascularity falls off much in the substance itself of the acinus; and is 
then repeated in the centre of the acinus in originating the corres- 
ponding branch of the hepatic vein. These preparations are now 
of many years standing. A similar exposition has been made by Du- 
jardin and Verger,* who assert that the parenchyma of the lobules, 
(acini) is absolutely without vessels and interior plexus, being 
made of oval gelatinous corpuscles, in the intervals of which the 
blood corpuscles move. 

The commencing radicles or ramifications of the Hepatic Duct, 
take their origin in the acini. The larger branches converge into 
their respective trunks successively or in pairs ; while the primordial, 
or most minute ones, converge several of them to the same point, 
giving a penicillous appearance. These several tubes constitute the 
Biliary Pores (Pori Biliari) and are always in the same group with 
the branches of the Vena Portarum and Hepatic Artery. It is un- 
settled whether these brush-like or penicillous ends of the pori biliarii 
are enlarged at their free extremities so as to be there like a pin at 
its head, in a manner so common in glandular structure. Krause 
asserts the fact, and states that the enlargement measures from 5 V to 
jfr of an English line, and there are said to be preparations of 
the kind in Utrecht. f It is asserted that a fine injection passes 
more readily from them into the lymphatics than into any other 
order of vessels; which may account for the promptitude of jaundice 
upon an obstruction of the hepatic duct. The most minute branches 

* Huschke ut supr. p. 124. 

f Miiller, Phys., p. 491. London, 1840. 



THE LIVER. 73 

of the biliary ducts in the acini are so close together that they seem 
to be united to one another, Their diameter, according to Muller, 
varies from V ff to is of an English inch ; they are, therefore, much 
larger than the finest capillary blood vessels. 

A case of obstruction of the hepatic duct by a medullary mass, in 
the practice of Professor Geddings of South Carolina, in arresting 
the bile produced a distention of the extreme biliary canaliculi, 
which were observed by him to commence in cceca closely impacted 
one against another.* 

The Venaj Portarum having arisen from the junction of all the 
veins of the stomach, intestines, pancreas and spleen, is about three 
inches in length when it reaches the transverse fissure, of the liver by 
going over the duodenum and under the pancreas. It immediately 
divides into two branches, called collectively the Sinus Vense Por- 
tarum, which is at right angles with the trunk of the vein. The right 
branch being the shortest and largest, is distributed by radiating 
trunks to the right lobe of the liver ; the left branch is distributed, 
after the same manner, to the left lobe, to the lobulus Spigelii, and 
to the lobulus quartus. Some of its branches anastomose with the 
hepatic veins, which accounts for the ease with which an injection 
will pass from one to the other. 

The vena portarum is finally reduced into extremely attenuated ca- 
pillary extremities, whose diameter is from jy 5 to its of a line in 
diameter according to Weber. They invest the acini, penetrate 
them to some extent, and anastomose freely together in observing 
this arrangement. Their meshes are occupied according to Weber 
almost wholly by the biliary canaliculi, but just doubts are now en- 
tertained whether they do more than come in contact with them, 
contrary to an opinion formerly held that they discharge into or anas- 
tomose with them. Their final termination is in the corresponding 
branches of the Hepatic veins, the freedom of which communication 
there is no difficulty in proving by injection as well as by the ordinary 
laws of the circulation of the blood. 

The Hepatic Artery is a branch of the cceliac, and in approaching 
the transverse fissure divides into three or more branches, that pene- 
trate the substance of the liver, between the sinus venae portarum 
and the ducts as they come out ; one branch goes to the right lobe, 

* North Am. Journ. 1835. 
f Anat. Atlas, Fig. 350. 



74 ORGANS OF DIGESTION. 

another to the left, and a third to the lobulus Spigelii. There is 
some variety in regard to the precise mode of distribution ; and their 
division into subordinate ramifications frequently occurs, before they 
get fairly into the substance of the liver. When there, they seem 
to be intended for the nourishment of this organ, and follow the 
ramifications of the vena portarum and of the biliary ducts, forming 
upon them a very delicate and complicated tissue of anastomosing 
vessels ; some of which, probably the vasa vasorum, communicate 
with the vena portarum. 

The hepatic artery having been reduced into extremely fine 
branches is found expending itself upon the walls of the vena por- 
tarum and of the biliary ducts ; it must of course, supply itself with 
nourishing blood, and also the parenchyma of the liver; and it finally 
makes a plexus in the case of each acinus intimately blended with 
the ultimate plexus of the vena-portarum, with which it has a free 
communication as readily proved by injection. There ought to be 
but little doubt that the vena portarum is the primary recipient of its 
blood. The analogy is established in the gall bladder, where the cystic 
artery discharges into the cystic vein : the latter then proceeding to 
the vena portarum, is sufficient proof of the compatibility of this ar- 
rangement. The venous vasa vasorum of the vena portarum is also 
in favour of it. But whether such termination is exclusively in the 
vena portarum may give rise to a question. 

Many of the finer branches of this artery (Rami serosi) reach from 
the interior to the surface of the liver, and running out a great length 
with almost uniform size make, under the peritoneal coat, a most 
beautiful and exquisite reticulation by their own branches, and those 
of adjoining vessels of the same kind. A reticulation so fine that it 
strongly resembles a lymphatic one. 

The Hepatic Veins arise in the acini from the capillary termina- 
tion of the vena portarum and the hepatic artery. Their branches 
are successively accumulated into three large trunks, the collective 
area of which vastly exceeds that of the vessels bringing the blood to 
the liver. Two of these trunks come from the right lobe and one 
from the left, to empty into the ascending cava, while it is still in 
contact with the liver, immediately below the diaphragm ; just below 
the preceding trunks there are five or six, sometimes more, small 
hepatic veins, coming from the posterior margin of the liver and 
from the lobulus Spigelii. The hepatic veins are destitute of valves, 
and lemarkable for the thinness of their parietes. An injection passes 



THE LIVER. 75 

readily from them into the other systems of vessels. They may be 
recognised by their insulated course, and by their consisting in trunks 
which converge from the periphery of the liver to the vena cava, while 
all the other vessels diverge from the transverse fissure to the peri- 
phery, and consequently cross the course of the hepatic veins. 

The larger branches of the venae hepaticse exhibits a remarkable 
number of very small branches with patulous mouths a sixth of a line 
or less in their diameter, which come directly from the contiguous 
acini; having arisen by still smaller extremities in connexion with 
the capillary terminations of the other blood vessels of the liver. 
The number of such foramina gives to the sides of the hepatic veins 
a cribriform appearance. The branches of the hepatic veins seem 
to free themselves more completely from their entanglement with 
the other vessels near the centre of the acinus, and then pursue a 
course to themselves not difficult to follow out. 

Owing to the involution of one set of the hepatic capillaries with 
another, there is an essential and almost insurmountable difficulty in 
forming a conception, or making a preparation which will elucidate 
their ultimate arrangement. In explanation of this difficulty Mul- 
ler considers that there is an ulterior plexus of capillary blood 
vessels with which the other three communicate freely, this is pro- 
bably the fact, including the lymphatic system also; but the precise 
mode of its formation is as yet not ascertained, an idea long ago ad- 
vanced by Chaussier in regard to all glandular structures. 

According to the valuable observations of Mr. Kiernan,* the acini 
of Malpighi should be called lobules, inasmuch as they consist in the 
collection of smaller granulated bodies, to which he restricts the 
name of acini. The objection to this principally is that it intro- 
duces a new definition, on a point heretofore considered as settled in 
the universal phraseology of anatomists. 

His statement then is that the finer branches of the vena portarum, 
which he calls Interlobular veins, make a perfect and minute plexus 
surrounding the lobules or small granular masses of the liver; they 
then form convergent lines of vessels directed towards the centre of 
each lobule and communicating by transverse branches with one 
another. These latter connexions or the sets of veins making them, 
constitute the lobular venous plexus, and in their intervals are placed 
what he calls the acini or subordinate granules. 

He says, also, that the Hepatic Duct forms a plexus upon the 

* Anat. and Physiol, of Liver, Phil. Trans. London, 1833. 



76 ORGANS OF DIGESTION. 

lobules like that of the vena portarum ; the plexuses of the contigu- 
ous lobules being indisposed to anastomose, though he thinks there 
is ground to believe in such anastomosis. The interlobular biliary 
ducts then penetrate the lobule and ramify by anastomotic connex- 
ions through it.* 

The Hepatic Artery, he says, makes also a plexus upon the surface 
of the lobule, and penetrates interiorly from its periphery towards 
the centre, to end in the vena portarum. Meckel says, that they end 
in the incipient branches of the venee hepaticse. 

The Hepatic veins, according to Mr. Kiernan, are seen as a small 
trunk in the centre of a lobule ; this trunk arises from the conver- 
gence of from four to eight venules, from the periphery to the cen- 
tre of the lobule. 

It is stated by Mr. Kiernan, that the elements of the above ar- 
rangement of ducts and blood vessels are formed very distinctly in 
the left lateral ligament of the liver. 

He appears not to have succeeded in injecting the hepatic veins 
from the hepatic artery, though he can inject them from the vena 
portarum. His injection was probably not fine enough, as there 
is not the slightest difficulty in filling all the ducts and blood ves- 
sels of the liver from either set, provided one throws in a very fluid 
injection ; the use of water simply will prove this beyond doubt. 

Mr. Kiernan's statements appear to have been received as decisive 
by his countrymen, both anatomists and physiologists, and by some 
of the continental anatomists; generally, without much apparent ex- 
amination for themselves. In some respects he has, judging from 
his figures, been peculiarly fortunate by finding in his dissections the 
lines of blood vessels upon the same plane and so clear; when their 
general course, according to common experience, is so tortuous, un- 
even, and implicated. 

A greater reserve has been manifested by the German teachers, 
thus there is a remarkable discordance between his observations on 
the incipient state of the biliary pores, and Krause's and Huschke's, 
the latter speaks pointedly of the ideal figure of Kiernan. Wagner, 

* According also, to Weber and Kroninberg, the incipient extremities of 
the biliary ducts make a net-work in the acini. Weber says, that the diame- 
ter of these branches, is from the 1-1340 to the 1-900 of an inch. That the 
blood capillaries have a diameter of from the 1-1959 to the 1-1463 of an inch, 
and that the distance passed by the bK5od from the smallest portal, to the 
smallest hepatic vein is from the 1-80 to the 1-70 of an inch. Mailer's Arch. 
4184. 




THE LIVER. 77 

of accomplished skill as an anatomist, in admitting that angular cells 
form the lobules, (acini) and that these are separated," one from 
the other, by cellular substance, asserts " that he finds it much more 
difficult to say how the different vessels — the last divisions of the 
vena portae, of the venae hepaticae, and of the ductus hepaticus com- 
port themselves in the interior of the lobules. I regard the beautiful 
figures and the descriptions of Mr. Kiernan, as the best and most 
accurate that have been published, although they very certainly also 
include many mistakes."* 

At the bottom of the transverse fissure of the 
liver is to be found a dense cellular fibrous tissue, Fi £- 28i 

which invests the vena portarum, the hepatic artery, 
and the biliary ducts ; and, as they all keep together 1 
in their ramifications, this tissue follows them 
throughout the substance of the liver, and thereby 
forms sheaths for them. It may be considered as Secreting cells 
continuous with the processes sent in from the eel- of the Human 
hilar coat ; and, contrary to the opinion of Glisson, lver ' *' " uc eus ' 
whose capsule it has been called, it is devoid of ii_ par ticles. 
muscular structure. 

The lymphatics of the Liver are large, numerous, and deprived 
of valves, hence they can be readily injected and make a brilliant 
close plexus on its surface, from which mercury soon subsides owing 
to the freedom of their communication with the deeper lymphatics. 
They leave it by various routes in large trunks which ascend and 
depart by the several ligaments. 

The nerves of the liver are branches of the solar plexus of the 
sympathetic, and reach it through the transverse fissure in com- 
pany with the blood vesels. 

The liver appears in the embryo to be originally formed by a 
protrusion of the walls of a part of the intestinal canal ;f the lung? 
and pancreas present a similar mode of evolution; 



Of the Gall- Bladder 4 

The Gall-Bladder ( Cystis Fellea) is a reservoir for the bile, secreted 
by the liver. It is fixed on the under surface of the great lobe, to 

* Elements of Physiol. London, 1842. 
f Muller, loc. clt, p. 400. 
% Anat. Atlas. Figs. 348, 349. 
Vol. II.— 8 



78 ORGANS OF DIGESTION. 

the right of the umbilical fissure, and removed from the latter by 
the lobulus quartus.* It is an oblong pyriform sac, having its 
anterior extremity or fundus projecting somewhat beyond the an- 
terior margin of the liver, while the posterior end reaches to the 
transverse fissure. Its long diameter inclines slightly to the right 
side, so that it is not precisely in an anteroposterior line. It varies 
in its shape in different subjects, being much more spheroidal in 
some than in others. Its fundus is rounded and obtuse, while the 
posterior end is gradually reduced to a narrow neck, which is bent 
upon itself, so as to retard the flow of a fluid through it. Its upper 
surface is in contact with the substance of the liver, and is received 
into a broad shallow fossa, while the lower surface is projecting, 
and by coming in contact with the transverse colon, tinges it with 
bile, by transudation after death. 

The Gall-Bladder has three coats, a peritoneal, a cellular, and a 
mucous one. 

The Peritoneal Coat is not complete, but only covers that part of 
the sac not received into the fossa on the under surface of the liver; 
it is, therefore, a continuation of the peritoneal coat of the latter; 
sometimes, however, the gall-bladder is so loosely attached to the 
liver that it almost hangs off" from it, in which case the peritoneal 
coat is nearly complete. 

The Second coat is condensed cellular membrane, (Tunica Pro- 
pria.) Through it ramifies a great number of lymphatics, and blood 
vessels; below, it attaches the peritoneal to the mucous coat, and 
above, the latter to the liver. 

The Mucous Coat is always tinged of a deep green or yellow, by 
the bile which it contains percolating after death ; for it is said to be, 
before that, of a light colour. This coat is thrown into irregular 
tortuous folds or wrinkles of extreme delicacy, in the intervals of 
which are many round or polvhedrous cells, causing it to look, when 
floated in water, like a fine honey comb : such as are about the 
fundus of the sac are superficial, and not so distinct; but those near 
its middle and about the neck, are a line or a line and a half deep. 
In the neck or apex, and in the beginning of the cystic duct, are 
from three to seven, sometimes twelve semilunar duplicatures of 
the internal membrane, which also retard the flux and afflux of any 

* I have seen an instance where it was to the left of the umbilical fissure, 
on the small lobe. The latter was much longer than common. Dec. 1830. 



THE LIVER. 79 

fluid, though they do not afford so much resistance to the ingress as 
to the egress of it. These duplicatures are sometimes partially ar- 
ianged into a spiral valve, projecting from the inside of the duct, and 
forming two or three turns.* Very small mucous follicles exist over 
the internal face of this membrane, the discharge of which fills the 
gall-bladder when the secretion of bile has been interrupted by dis- 
eased action, as in yellow fever, or by scirrhus of the liver. 

The artery of the gall-bladder is a branch of the hepatic. Its 
veins empty into the vena portarura. Its nerves come from the 
sympathetic, and its lymphatics join those of the liver. 

The gall-bladder is developed as a diverticulum, from the Hepatic 
Duct. 

Of the Bile Ducts. 

A succession of very fine branches having arisen from the acini 
of the liver, these branches are united into three or four trunks by 
the time they reach the transverse fissure. The trunks then coalesce 
into a single Duct, the Hepatic, of eighteen or twenty lines in length, 
and about the diameter of a writing-quill. The Hepatic Duct is then 
joined at a very acute angle with the Cystic duct or that from the 
gall-bladder, which is somewhat shorter and smaller; the union of 
the two forms the Common Duct, [Ductus Communis Choledochus.) 
The latter is larger than either of the others singly, and is three or 
three and a half inches long ; it descends behind the right extremity of 
the pancreas through its substance, passes nearly an inch, obliquely, 
between the coats of the duodenum, becoming at the same time 
diminished in diameter; and, finally, ends by an orifice still more 
contracted, on the internal face of this gut, at its second turn, and 
about three or four inches from the stomach. The orifice is marked 
by a small surrounding tubercle somewhat obscured by the valvulae 
conniventes. 

The Hepatic, the Cystic, and the Common Duct are situated, as 
mentioned, along the right margin of the lesser omentum, and have 
the vena portarum and the hepatic artery to their left. 

The bile ducts are formed by two coats ; the external is a fibrous, 

* Discovered by M. Amussat, of Paris. He has also detected muscular 
fibres in the gall-bladder and biliary ducts, in which we see an analogy with 
other hollow visoera. — Am. Jour. Med. Sciences, Vol. ii. p. 193. 



80 ORGANS OF DIGESTION. 

lamellated, and very extensible membrane, while the internal is 
mucous, having the same structure with that of the gall-bladder, of 
which it is in direct continuation. In the Cystic Duct, and at the 
lower part of the Common Duct are several longitudinal folds. The 
Common Duct sometimes receives, just before it empties into the 
duodenum, the Pancreatic Duct. 



Of the Bile, 

This secretion from the liver, is of a deep yellow, sometimes 
green colour : when recent, it is thin and fluid ; but after it has been 
conveyed to the gall-bladder, and permitted to remain there for 
some time, it becomes as thick as molasses, and increases also in 
the intensity of its colour and in bitterness. Some anatomists have 
believed that there was a more direct communication between the 
liver and the gall-bladder than that through the hepatic and the 
cystic duct ; but repeated and close observations have proved the 
opinion to be erroneous, or at least destitute of proper proof: it is 
therefore, clear, that the difference between the hepatic and the 
cystic bile, depends upon the watery particles being removed from 
the latter by the absorbing power of the internal coat of the gall- 
bladder. 

According to Berzelius, the chemical analysis of bile furnishes 
about eighty parts of water, eight of a particular substance, Biline, 
which assumes a resinous condition on the application of an acid: 
three of mucus ; and nine of saline matters ; of which soda is a 
principal constituent. 



SECT. II. — OF THE SPLEEN.* 

The Spleen, {Lien, Splen,) is situated deeply in the posterior part 
of the left hypochondriac region, and is bounded above by the dia- 
phragm, below by the colon, and on the right by the great end of 
the stomach, and by the pancreas. It is not ascertained that it 
secretes any thing. 

Its colour varies from a deep bine to a dark brown. In shape 
it resembles the longitudinal section of an oval, being flat or very 

* Anat. Atlas, Figs. 351 to 334, inclusive. 



THE LIVER. 81 

slightly concave on the surface next to the stomach, and convex on 
that contiguous to the diaphragm. Occasionally its margins are 
notched, but this is not invariably the case. Its flat surface is 
slightly depressed longitudinally in the centre ; into a fissure which 
is imperfect, and where the blood vessels enter into it, by six or 
eight foramina. 

Several spleens sometimes exist in the same individual, in which 
case the supernumerary ones are not larger than nutmegs. The 
common size of this organ is about four and a-half inches long, by 
two and a-half or three wide, in which case it has a solid firm feel ; 
but it very often exceeds these dimensions; its transition and va- 
rieties of magnitude are so frequent, that no settled rule can be 
established. In its inordinate enlargements I have seen it only a 
little smaller than the liver; its texture in this case is soft and easily 
lacerated. 

It is fixed in its place by three lines of reflection or processes 
of peritoneum, called ligaments, whose names indicate their places 
of attachment. They are the Gastro-Splenic Ligament or Omen- 
tum, which passes from the stomach to the spleen, and in which 
are the vasa brevia of the stomach : the Splenico-Phrenic Liga- 
ment, which goes from the spleen to the diaphragm, attaching itself 
to the latter at the left of the oesophageal foramen, and then descending 
along the posterior internal face of the spleen, in a line, behind the 
gastro-splenic ligament: and the Splenico-Colic Ligament, which 
passes from the spleen to the colon, being, as it were, a process iron! 
the left extremity of the gastro-colic omentum. These reflections, 
by being continued over the spleen, give it a complete peritoneal 
coat, which is raised up w T ith more difficulty than the corresponding 
membrane of any other vise us of the abdomen, and is commonly 
thrown into very small inequalities or wrinkles. 

The internal or proper coat of the spleen is a grayish, compact, 
extensible, and elastic membrane, the use of which is evidently to 
sustain the natural shape of the organ, and to support its parenchy- 
matous structure. It sends in processes to accompany the blood 
vessels (capsular Malpighii) and from its internal face there proceeds- 
a multitude of lamella? and of fibres, which traverse its cavity in 
every direction, and reduce it into a cellular condition, not unlike 
the cavernous structure of the penis. 

Of the Intimate Structure of the Spleen. — The spleen, in propor- 
tion to its size, is furnished to a remarkable degree with blood. The 



82 ORGANS OF DIGESTION. 

largest branch of the cceliac artery runs to it along the superior mar- 
gin of the pancreas, forming numerous serpentine flexures, and dis- 
tinguished for its thickness and size ; it divides into several trunks 
before penetrating into the spleen, and enters by the foramina in the 
fissure. The veins come out by a number of trunks equal to what 
the artery is divided into ; they assemble then into a single trunk, 
which attends the artery along the pancreas, is destitute of valves, 
and empties into the vena portarum. 

The Splenic artery having penetrated into this organ, is divided 
and subdivided into a radiating succession of very fine branches, 
which, according to the injections of Ruysch, do not anastomose 
with each other ; in consequence of which one part is sometimes 
finely injected and not another. This corresponds with my own ob- 
servations. The veins, on the contrary, do anastomose, not only as 
regards the collateral branches of the same primitive trunk, but also 
by the collateral branches of different trunks. These anastomoses 
are not large. The veins of the spleen are remarkable for the tenuity 
of their coats, and for the great disproportion of their area, with that 
of the arteries, which in the larger trunks is rated at five to one, and 
in the smaller at twenty to one. The larger veins look cribriform 
when viewed from their interior, owing to the number of fine branches 
which they receive. 

The veins of the spleen, in their ramifications through this organ, 
besides their frequent anastomoses, undergo sinus-like enlargements, 
approaching the structure of the corpus cavernosum penis, and their 
walls are formed merely from the internal venous coat. The ar- 
teries terminate freely in the veins, as may be proved by fine injec- 
tions, and by the microscope. 

The mass of the spleen upon superficial examination, seems to 
consist in a dark brown bloody pulp, (Substantia rubra) which is 
contained in the cells dividing the cavity of the internal coat, and 
may be easily demonstrated by tearing or cutting the spleen, and 
scraping it with a knife handle. 

The pulpy substance of the spleen under the microscope, is com- 
posed of small spheroid or oval granules of a reddish brown colour, 
and about the size of the globules of the blood. According to Mr. 
Gulliver,* they are more unequal in size than the blood discs their 
diameter varying from 1-6000 to 1-1777 of an inch, and they are 

* Gerber's Genl. Anat. p. 102. 



THE SPLEEN 83 

found in blood taken from the splenic vein. They are easily sepa- 
rated from one another. 

The minute arteries of the spleen ramify in tufts among their gra- 
nules, and then terminate in a plexus of venous canals whose walls 
are so thin that the veins appear as mere channels in the pulp. 

A question has arisen whether the pulp (substantia rubra) be extrava- 
sated in the cells which contain it, or whether it be still retained in the 
extremities of the blood vessels. Superficial examination is in favour 
of the first, but M. Marjolin denies it on the following grounds; that 
injections, cautiously made, pass immediately from the arteries into 
the veins ; and that the spleen, when successfully injected and frozen 
does not exhibit ice in the interstices of its vessels, while their capil- 
lary ramifications distended by the injected fluid, are distinctly seen. 
From these facts he concludes that the glandular structure of the 
spleen is formed essentially of arterial and venous capillary vessels 
with very delicate and extensible coats; that they communicate with 
one another without the intermedium of any cell ; and that the 
extreme tenuity of these vessels, and their extensibility in every di- 
rection, are sufficient to explain the augmentation of volume of the 
spleen, under certain circumstances, as well as the promptitude of 
its diminution under others. 

MM. Assolant and Meckel believe that blood besides being in 
the arteries and veins, is placed in a state of particular combination 
and of intimate union with the other organic elements of this viscus, 
and with a large quantity of albumen ; and that this combination of 
the blood forms the dark brown pulp alluded to. The great quan- 
tity of albumen in the pulp, is readily proved by the hard coagulum 
which it forms, when steeped in alcohol. 

In addition to this pulp, many observers have met in the spleen 
with an abundance of rounded corpuscles, (Corpuscula Malpighii,) 
varying in size from an almost imperceptible magnitude to a line or 
more in diameter.* They are of a gelatinous consistence, soft, 
grayish, and semi-transparent, and either cluster together, or are 
widely separated and have a diameter of from one-sixth to a third of 
a line. Their exact structure is undetermined. By Malpighi, they 
were considered glandular, and by Ruysch,,f as convoluted vessels. 
Professor Soemmering from th,e following paragraph, seems to join 

* Malpighi, Ruysch, Hewson, Home, Dupuytren, Meckel,, &c. 
f Epis. Anat. IV. 



84 ORGANS OF DIGESTION. 

in the opinion of the latter : " Qui nonnunquam oecurrunt, acini vel 
glomeruli, microscopii ope accuratissirae explorati, nihil sunt nisi 
vasorura fasciculi, vel teretes penicilli aut cirri vasculosi." Accord- 
ing to the observations of Sir Everard Home, they swell consider- 
ably after an animal has finished drinking. 

The corpuscles are seen with difficulty in the human spleen, in 
animals they are much more distinct, as in the hog, sheep, and ox. 
Muller* admits their connexion with the arteries, but is inclined to 
consider them as excrescences from their coats, as in his injections 
the arteries were seen to pass through, but not to ramify in them. 

Their real existence has been much contested, owing to the un- 
certainty of finding them, but it now seems to be admitted, that the 
best spleens for this purpose are such as are perfectly healthy, and 
taken from subjects who have died suddenly. A little delay dis- 
poses them to become putrescent, and more pulpy, as it does the 
red substance of this organ. Those of a brownish red are best 
suited for the investigation. 

The corpuscles of Malpighi are at least vesicles, with very thin 
parietes, hence when punctured, their fluid which is found of an al- 
buminous character, escapes, and they collapse. They are some- 
times in a group of six, suspended to an arterial ramuscule like a 
pedicle. The vessels do not penetrate them but are confined to 
their exterior, where they form a very fine net-work. The fluid 
which they contain, is according to Bischoff and Huschke, white, 
with a multitude of globules swimming in it, and looking very much 
like chyle. Huschke after much inquiry into their structure, considers 
it most probable that they are dilatations of the lymphatic vessels of 
the spleen, from their analogy with the interior of a splenic or me- 
senteric lymphatic gland of an infant; and he thinks all that remains 
to verify the conjecture is an obvious connexion with some lymphatic 
vessels, afferent and efferent. By Simon they are considered as 
aggregations of Cytoblasts.f 

The spleen has many lymphatic vessels; and is furnished with 
nerves from the solar plexus. 

The spleen, from having no excretory duct, and consequently, from 
our inability to ascertain whether it secretes, has its uses unknown. 
No single theory concerning it has ever been generally adopted, for 
speculations have multiplied in proportion to the obscurity of the 

* Physiol, p. 618. f Brit, and For. Med. Rev. p. 567. April, 1816. 



THE SPLEEN. 85 

subject. By some it is thought to exercise merely a mechanical 
function — by others, a chemical one — by others, a dynamic — and 
in the midst of such uncertainty, some have concluded that it 
had no special function. The hypothesis which to me is most 
reasonable, is, that of its acting a subsidiary part to the liver. It 
would seem, indeed, as a general rule in regard to glandular struc- 
tures and such other highly vascular organs of the body as have an 
intermittent function, that the blood which is sent to them during 
their state of activity, should be passed off through a different 
channel, while they are in a state of repose. This does a double 
service, it prevents superfluous secretion, and it also keeps up the 
vascular equilibrium of the body; as there must be always in readi- 
ness a quantity of blood sufficient for the supply of any secretion 
which may be wanted for the time. 

This proposition will derive some additional illustrations from the 
foetal state. The kidneys being then inactive the capsulae renales 
take off' their blood, and thereby prevent what would otherwise be 
a very inconvenient secretion of urine; again, the lungs being also 
then inactive, the circulation through them is proportionately re- 
duced, and the superabundant blood is conducted through the thy- 
mus gland. But as the full functions of the. lungs and of the kidneys 
are established upon birth, and continue uninterrupted during life ; 
their supplementary organs respectively, as the thymus gland, and 
the capsulae renales, not being wanted ; wither away after the early 
period of infantile existence is passed. 

In regard to the liver, its functions also suspended during the 
foetal state, are of an intermittent kind throughout life, the spleen 
may, therefore, be considered a vicarious organ for it, during the 
whole period of existence; receiving its blood during the continua- 
tion of uterine life, and in the intermission of action, during common 
life. The spleen is, therefore, an organ useful to the foetal and to 
the perfect state, and we, consequently, never see it in the collapsed 
and effete condition of the thymus gland, and renal capsules. 

The same reasoning which applies to the spleen, will also apply 
to the Thyroid Gland : the latter may be considered as executing for 
the salivary glands during foetal and perfect existence, what the 
spleen does for the liver. For the salivary glands being inactive 
during foetal existence, have only an intermittent action during per- 
fect life; and, therefore, probably stand in need of a supplementary 
organ during their periods of inactivity. 



86 ORGANS OF DIGESTION. 

SECT. III. — OF THE PANCREAS.* 

The Pancreas (Pancreas) secretes saliva, and is the largest of the 
salivary glands. It is fixed in the lower back part of the epigastric 
region ; and extends horizontally across the spine, being separated 
from it by the lesser muscle of the diaphragm. It is connected to 
the spleen on the left ; at its right extremity is surrounded by the 
curvature of the duodenum; is bounded in front by the stomach, 
which conceals it; and is placed between the two laminse of the 
mesocolon. 

The pancreas is about six or seven inches long, two wide, and 
flattened before and behind. Its figure would be represented by a 
parallellogram, were it not that its right extremity is enlarged con- 
siderably into a head or tuber, to which Winslow gave the name of 
the Lesser Pancreas. The anterior face of this organ is turned ob- 
liquely upwards, and is covered by the superior lamina of the meso" 
colon. The posterior face looks obliquely downwards, and is in 
contact with the aorta, the vena cava ascendens, the superior mesen- 
teric vessels, and several nerves : along the superior margin of this 
face exists a long superficial fossa, occupied by the splenic artery 
and vein. 

With the exception of the loose covering given by the meso- 
colon, the pancreas has no peritoneal coat; neither has it an ap- 
propriate tunic, unless we consider as such the lamina of con- 
densed cellular membrane which envelops it, and sends in processes 
between its lobules, as in the case of the salivary glands in the 
neck. 

Of the Minute Structure of the Pancreas. — This body, like the 
other glands, which discharge saliva, is of a light gray or pink 
colour. It consists in lobules of various forms and sizes, united 
by an intermediate cellular tissue, and having their interstices occu- 
pied by numerous blood vessels. These lobules, by a slight mace- 
ration, may be separated and resolved into small granular masses, 
constituting integral portions of the gland. 

The arteries of the pancreas come principally from the splenic, 
as it cruises along the superior margin. The veins empty into the 

* Anat. Atlas, Fig. 354. 



THE SPLEEN. 87 

splenic, and thus, finally, into the vena portarum. It is furnished 
with nerves from the solar plexus, and has lymphatics. 

The excretory duct of this gland (Ductus Wirsungii) arises, by 
very fine roots or tubes, from each of the small granular masses. 
These roots have vesicular commencements like those of the sali- 
vary glands. The tubes coalesce into larger ones, which run trans- 
versely from the periphery towards the centre of the gland, inclining 
slightly, at the same time, towards the right. These secondary tubes 
finally discharge successively into a single one, which runs the whole 
length of the gland nearly in its middle. The single tube, by these 
additions, enlarges continually from left to right, being small where 
it begins at the splenic extremity of the pancreas, and about the size 
of a crow-quill at the duodenal. At the latter place, it is joined by 
the duct of the lesser pancreas, which is derived after the same rule 
as itself. The pancreatic duct, almost immediately afterwards, emp- 
ties into the ductus communis choledochus ; or runs at the side of 
the latter, and makes a distinct opening near it into the duodenum, 
at the posterior part of the second curvature. 

The diameter of the cell-like extremities of the duct of the Pan- 
creas is from six to twelve times greater than that of the capillary 
blood vessels. 



BOOK V. 



OF THE URINARY ORGANS. 



The Urinary Organs, (Organa Oropoietica) being destined to 
secrete and convey the urine out of the body, consist in the Renal 
Capsules, the Kidneys, the Ureters, the Bladder and the Urethra. 



Of the Renal Capsules. 

The Renal Capsules (Capsules Renales, Renes Succenturiati,) are 
two small bodies, one on either side, placed upon the upper end of 
the kidney. They are of a yellowish brown colour tinged with red, 
have no excretory ducts, and are more distinctly developed and 
softer in the perfect foetus than in the adult ; whence they are ranked 
among those organs, as the thymus gland, and others ; which, having 
some peculiar value in foetal existence, are perhaps unnecessary to 
that of the adult.* They are of a triangular pyramidal shape, flat- 
tened before and behind, and rest by a concave base upon the kid 
neys ; they are about fifteen lines high and as many wide. 

They are surrounded by a proper coat of lamellated dense cel- 
lular tissue, which, by detaching inwards its prolongations, keeps 
the parts of these bodies together, and marks out their divisions. 
In the centre of the renal capsule, a cavity may, from time to time, 
be found ; but, according to my own observations, nothing in our 
structure is less certain than its existence ; and, in the opinion of 
Meckel, when found, it is the result of cadaverous decomposition. 
In the foetus it contains a reddish viscid fluid, which seems to con- 
sist in a large share of albumen, as it coagulates with alcohol; in 

* This opinion has been confirmed in a dissection of a foetus, where I found 
the capsulae renales, though the kidneys were absent. 
Vol. II.— 9 



90 



URINARY ORGANS, 



children, this fluid becomes yellow : in adults it is dark brown ; and 
in old people it is either entirely deficient, or in a remarkably small 

quantity. 

Of the Minute Structure of the Capsula Renales.— The arteries 
of these bodies come from the emulgents, from the phrenics, and 
from the aorta. The veins of the right one terminate in the cava 
ascendens, and of the left in the left emulgent. Each one is divisible 
into lobes, and by a slight maceration may be reduced into lobules 
and small granulations. The granulations seem to have an intimate 
connexion with the veins, as they are easily penetrated by fluid in- 
jections from the latter. The external part is rather more consistent 
and yellow than the internal ; hence, a division has been adopted 
into cortical and medullary portions. 

In the cortical portion, the minute arteries and veins are about 
the size of the capillaries of other parts, and are of nearly uniform 
magnitude. They are arranged in a radiated manner, so as to run 
in lines from the surface towards the centre. The arteries anasto- 
mose with the adjoining branches, so as to form very long meshes: 
the veins do the same. On the periphery of the organ there is an 
ordinary capillary net-work of vessels. A spongy venous tissue 
composes the greater part of the medullary or more interior portion ; 
this spongy tissue receives the radiated venous branches of the ex- 
terior, and discharges its own blood into a large vein (Vena supra- 
renalis) in the interior of the organ. Muller,* in addition to the 
above, says that the only cavity in this organ is the vein just alluded 
to, and that by forcing air into the vein the whole medullary tissue 
may be distended. 

Examination with the microscope, by Mr. Gulliver, f exhibited the 
proper structure or pulp as formed of spherules, from the n .fo v to 
the uooo of an inch. 

Alleged excretory ducts for these bodies have been found going 
to the testicle, to the pelvis of the kidney, and to the thoracic duct, 
but no credit is now attached to such assertions. 

* Physiol., p. 621. 

f Gerber's General Anatomy, Appendix, p. 103. London, 1943. 



THE KIDNEYS. 91 



Of the Kidneys .* 

The Kidneys (Renes) are two glandular bodies for the secretion 
of urine, fixed one on either side of the spine. They are in the 
back part of the lumbar regions, have their internal edges inclining 
very slightly forwards, and extend from the upper margin of the 
eleventh dorsal to the lower margin of the second lumbar vertebra: 
the right, however, is ten or twelve lines lower than the left, owing 
to the thick posterior margin of the right lobe of the liver, which 
presses it downwards. The kidneys are covered in front by the 
peritoneum and the lumbar portions of the large intestine, but in 
such a manner as to be separated from them, in corpulent subjects, 
by a surrounding layer of fat ; behind, they repose upon the lower 
part of the great muscle of the diaphragm, upon the quadrati lum- 
borum, and upon the upper end of the psoae magni muscles. 

The kidney is a hard solid body, of a brown colour ; in shape it 
is a compressed ovoid, excavated on the margin which it presents 
to the spine, and bears a very strong resemblance to the common 
kidney bean. Its flat surfaces present forwards and backwards, and 
the broad end of the ovoid is above. Its periphery is smooth, so 
that one does not infer from an external examination, the lobules or 
internal divisions. The excavation of the kidney, next to the spine 
and called its fissure, (hilum renale) occupies about one-third of its 
long diameter, is bevelled in front, and leads to the very interior of 
the gland; conducting its blood vessels and excretory duct, which 
have to pass through a quantity of cellular and adipose matter. The 
kidneys are generally of equal size, being about four inches long, 
and two wide ; and each one weighs three or four ounces. They 
have no ligaments for keeping them in position, but depend for the 
latter upon the adjacent cellular adhesions and blood vessels. 

The kidney being destitute of a peritoneal coat, has a well marked 
capsule which envelopes it entirely and penetrates into its fissure for 
some depth, where it is perforated with foramina for transmitting the 
blood vessels and the ureter. This capsule is white, semi-trans- 
parent, fibrous, strong, and elastic : it adheres to the surface of the 
kidney by delicate cellular and vascular filaments, which are so 
weak that they permit it to be stripped off without difficulty, and 

* Anat. Atlas, Figs. 35G to 3G8, inclusive. 



^ 



92 URINARY ORGANS. 

when so removed, some indications of a tabulated condition of the 
organ are seen. 

Of the Minute Structure of the Kidney.— The tabulated state of 
the kidney is well marked in the foetus ; and some of the lower orders 
of animals, as the bullock, exhibit it very clearly through life. In 
the human adult subject, by tearing the kidney up according to the 
superficial lines marking a tendency to the tabulated condition, it 
will be found that there are really about fifteen divisions of it, more 
or less, each of which constitutes a small kidney (Renculus.) When 
the kidney is cut open longitudinally, it obviously consists of two 
kinds of substance, differing in their situations, colour, consistence, 
and texture. The one making the periphery of the gland is called 
from its position Cortical, (Substantia Corticalis, Glandulosa,) while 
the other, being more internal, is designated as the Medullary or 
Tubular, (Substantia Medullaris ; Tubulosa ; Fibrosa.) 

The Cortical or Secretory Substance forms the whole circumfer- 
ence of the kidney, and, on an average, is about two lines in thick- 
ness; but it is thicker at some points, as, from its internal face, pro- 
cesses converge towards the centre of the gland, which separate the 
tubular part into as many distinct portions of a conoidal shape. It 
is composed largely of arteries and veins ramifying, among small 
granular corpuscles (Corpora Malpighiana, or Glomeruli.) It tears 
with facility, thereby presenting this granular appearance, and is of 
a dark or reddish brown colour, varying considerably, however, ac- 
cording to the cause of death. 

The Granular corpuscles which form the mass of the cortical or 
secretory substance, are, individually, merely visible to the naked 
eye; but are very distinct when viewed with a microscope. They 
present themselves as innumerable small round points more red 
than the other portions of the surface inspected. Their diameter 
approaches the tenth of a line, some being less. They are attached 
to very fine arterial twigs, like a berry to its stem, and are so dis- 
engaged in their position in the cortical part of the kidney that they 
may be lifted out of their beds with the point of a needle, especially 
in the horse. 

The celebrated Ruysch, who was distinguished for the success of 
his injections, and for the acuteness of his vision, declared that they 
consisted wholly in clusters of very fine extremities of arteries 



THE KIDNEYS. 93 

and veins having a penicillous arrangement; while Malpighi and 
Schumlansky viewed them as purses or small sacs of a glandular cha- 
racter, specifically suited to secrete urine, and upon whose parietes 
the blood vessels ramified. From these granuli or acini the incipient 
extremities of the tubuli uriniferi, they asserted, take their rise. 

The Tubular or Conoidal Substance, consists in from twelve to. 
eighteen conoidal fasciculi, say on an average fifteen (Pyramides 
Malpighiance) presenting their rounded bases towards the cortical 
matter, and enclosed in it, while their apices converge to the central 
cavity of the kidney, the surface of which they form. The bodies 
of these pyramids, as just mentioned, are separated by processes of 
the cortical matter; but their apices are free, and project from the 
internal surface of the kidney so as to resemble as many small nip- 
ples, whence they are called Papillae or Mammellae Renales. Fre- 
quently two of the pyramids coalesce so as to form but one papilla 
together ; in such case the latter generally preserves a duplicate ap- 
pearance. The papillae are arranged into three vertical rows, one 
before, one in the middle, and another behind; those of the foremost 
row are turned backwards ; those of the middle look inwards ; and 
those behind look forwards. Not unfrequenfly, there is a small de- 
pression {foveola) on the very summit of the papilla. The tubular 
part is of a lighter colour and harder than the cortical, but the dif- 
ference in these respects is not always manifest and sometimes is 
reversed. 

The conoidal fasciculi may each be considered, along with its 
appertaining cortex, as a sort of distinct gland (Rencuhis,) or at least 
as a lobe ; for upon them depends the lobulated appearance as stated 
of the kidney of a fetus, and of animals. Each cone, when analy- 
zed, is found to consist in a collection of tubes (Ductus Uriniferi 
Bellini) converging from the circumference of the kidney to the apex 
of the papilla. These tubes are more numerous near ihe base of the. 
cone, in consequence of their successive junction subsequently in 
approaching the apex:* their terminating orifices, on the latter, ap- 
pear like small pores from which the urine can be squeezed in little 
drops. 

In the early part of the course of the ductus uriniferi, while they 

* Schumlansky, Diss, de Struct. Renum, Strasburg, 1782. 
9* 



94 



URINARY ORGANS. 



are still in the cortical matter, they are wound about in a very ser- 
pentine and tortuous manner, and are distinguished by the name of 
Cortical Canals, (Ductus Ferrenii*) They there commonly go alone, 
winding their way in the cortical substance until they reach its most 
interior face; they then become straight, form the tubular substance, 
and have the name of the conduits or uriniferous ducts of Bellini.f 

Some of the calculations on this subject are not a little curious. 
It was ascertained by Ferrein that in each of the conoidal fasciculi 
(Pyramides Malpighiance) there were, at least seven hundred subor- 
dinate cones or pyramids, (Pyramides Ferrenii) and as the number 
of conoidal fasciculi is generally about fifteen, these pyramids would 
amount to ten thousand five hundred. Again, each of the subordi- 
nate pyramids is composed of many hundred uriniferous tubes, and, 
by the observations of Eysenhardt,J each of these tubes consists of 
twenty smaller ones. 

The cortical canals or ducts of Ferrein, it is believed by many, 
terminate at their peripheral extremity, by forming loops upon them- 
selves, and anastomoses with contiguous similar canals. § It is also 
held by some, as Wagner, that in addition to this mode of termina- 
tion others of those canals end in casca or blind extremities, which 
are either single or bifid. Should the observations in this respect 
turn out correct, the arrangement has been at least found more de- 
cided and frequent in the lower animals than in man. 

Huschke|| and John Miillerll have denied the connexion of the 
Granular corpuscles with the Ducts of Ferrein. The former says that 
if the ureter be injected by the pneumatic machine, the injection will 
be found never to reach the Malpighian corpuscles, though an injec- 
tion of the arteries at the same time will, and the two injections will 
remain apart. He hence infers that these bodies are merely the 
twisted tufted ends of the blood vessels, being an arrangement 
preparatory to the real secretion of urine from a subsequent capillary 
network, made of arteries and of veins. This network surrounds 
the cortical canals, and is displayed upon them, without, however, 
anastomosing with them. In opposition to this view, besides the 

* A. Ferrein; sur la Structure des reins et du foie. Mem. de l'Ac. des 
Sc. Paris, 1749, 

\ L. Bellini, de Structura Renum Florence, 1662. 

\ De Struct. Renum Obs. Micros. Berlin, 1818. 

§ Muller, Krause, Owen, Weber, See Muller's Physiol. 2nd ed. p. 496. 

|| Traite de Splanch. p. 298. 

f De Gland Struct, Leips. 1830. 



THE KIDNEYS. 



95 



testimony of preceding anatomists, we have a very good paper, by 
W. Bowman, of King's College, London,* showing by injections 
this connexion of the corpuscles and the ducts of Ferrein; and that 
the arteries and veins make there a tufted junction with one another. 
He asserts that each one of these corpuscles is actually included 
in the extremity of an uriniferous tube, which enlarges to receive 
it, that the arterial filament that supplies it after forming its tuft 
emerges as an efferent trunk, and is then merged in the capil- 
lary plexus investing the uriniferous tubes. This view has been 
measurably confirmed by Gorlach.f 

It appears that in the Boa Constrictor, there is a vena portarum to 
the kidney — some approach to which Bowman considers to exist 
in the human subject, under an arrangement stated by him. 



The Kidney receives from the aorta one 
or more branches, called the renal or emul- 
gent arteries, which divide as they approach 
the fissure ; and having got into the substance 
of the gland are distributed by innumerable 
twigs to all parts of it. The veins equal in 
number the arteries, and are somewhat larger. 
When both, or even one, of these systems of 
blood vessels is injected with wax and cor- 
roded, its branches are so abundant as to re- 
tain the form of the gland. In engaging in 
the fissure of the kidney, the arterial ramifi-^ 
cations are in front, the veins in the middle, 
and the commencement of the ureter be- 
hind^ The artery on the right side is 
longer than that on the left. The reverse is 
the case with the emulgent veins, as they 
empty into the vena cava ascendens. This 
arrangement is owing to the relative position 
of the aorta and the vena cava aseendens, as 
the first is on the left side of the spine, and 
the last on the right side. 

The arteries of the kidney, in ramifying 



Fig. 294 




Arrangement of the Re- 
nal vessels; in the Kidney 
of the Horse: — a, branch 
of Renal artery ; af, affe- 
rent vessel ; m, m, Mal- 
pighian corpuscles; ef, ef, 
efferent vessel s;p, vascu- 
lar plexus surrounding 
the uriniferous tubes; st, 
tube of Bellini, ct, tube 
of Ferrein. 



* Transactions Royal Society, London, part 1st, 1842. 
f Am. Journ. Med. Sciences, p. 442. April, 1846. 
X According to Bowman magnified about thirty diameters. 
§ This rule is subject to frequent variations. 



96 > URINARY ORGANS. 

minutely through its structure, adopt the following arrangement. 
They first of all pass through the processes sent inwards from the 
cortical matter between the Pyramids of Malpighi, or large cones 
and, having got fairly into the cortical matter, they divide into very 
fine twigs, which form arcades around the bases of the pyramids of 
Ferrein, and pass between them.* These arcades have anastomoses 
with each other, and their larger branches go almost exclusively to 
the cortical substance, but few of them bei$g found on the tubular. 
The branches radiate from the convexities of the arches, so as to 
surround the base of each cone, and to penetrate to the surface of 
die kidney. Some of these branches terminate in corresponding 
veins, and others on the granular corpuscles or acini. 

The connexion between the corpuscles and the arteries, has been 
compared to that between grapes and the stems on which they grow, so 
as to form a bunch. The veins penetrate the substance of the kidney, 
and have a similar distribution ; but they are much larger than the 
arteries, and have free, large and numerous anastomoses. A con- 
nexion of the corpuscles with the veins is not quite so evident, and, 
even if it does exist, remains yet to be adequately proved ; at least, 
in the opinion of many anatomists. The fact, however, is well esta- 
blished, that fine injections will readily pass from the veins into the 
tubuli uriniferi; and that air blown into the ureter will pass readily 
into the veins. In my own injections these have been done repeatedly, 
and the corpuscles of Malpighi are seen very distinctly to be formed 
of convoluted arteries; I have not seen the veins convoluted under 
the same arrangement, neither have I succeeded in tracing the corti- 
cal canals to these corpuscles or acini. 

From the concave side of the arterial arcades very fine capillary 
branches converge in company with the ducts of Bellini in a line 
with them, and penetrate to the free surface of the papillae renales. 
Upon this surface is made a highly attenuated capillary intertexture, 
the meshes of which surround the orifices of the tubuli uriniferi. The 
converging arteries anastomose across the tubuli, making elongated 
meshes. A similar arrangement of the veins takes place from their 
cortical branches and arcades, it being in company with the arterial 
arrangement. The facility of injecting these minute tubular arteries 
and veins has frequently given rise to the mistake of considering them 
as the tubuli uriniferi themselves ; an error which has been pointedly 
marked out by Miiller.f 

* Schumlansky. f Physiol, p. 225. 



THE KIDNEYS. 97 

The nerves of the kidneys come from the solar plexus of the sym- 
pathetic ; and adhering to the arteries cannot be traced very far 
through the glandular structure. The quantity of lymphatics is con- 
siderable. 

The kidneys are subject to a false position ; in one instance, I 
found in a young female subject, one of the kidneys in the pelvis in 
front of the rectum. A similar case has been seen by Professor Hen- 
singer,* and since then, others have been recorded. I have met with 
several instances of a coalition of the two kidneys, across the spine, 
so as to present the appearance of a bilobed organ. 

Of the Excretory Duct of the Kidney, or the Ureter.] 

The Ureter is a canal which conveys the urine from the kidney to 
the bladder. It commences in the centre of the kidney by an en- 
largement called pelvis, which branches off into three or four por- 
tions, (calices,) one above, one below, and one or two intermediate. 
Each of these calices, is divided at its free extremity, into three or 
four short funnel-shaped terminations, {Infundibula.) Each of these 
terminations embraces by its expanded orifice, the base of a papilla 
renalis, so as to permit the latter to project into it, and thereby to distil 
its urine there. Very frequently the number of papillae exceeds that of 
the infundibula, in which case two of the former project into one of 
the latter. 

The pelvis of the kidney having emerged at the fissure behind the 
vessels, from being expanded and conoidal in shape is reduced to a 
cylindrical canal, which, properly speaking, is the ureter : the latter 
is about the size of a goose-quill, and descends through the lumbar 
region, between the peritoneum, and the psoas magnus muscle. It 
dips into the pelvis by crossing in front of the primitive iliac vessels 
and the internal iliac, crosses the vas deferens at the back of the 
bladder, and penetrating obliquely the coats of the latter, terminates 
in an orifice ten or twelve lines behind that of the neck of the 
bladder. 

The excretory duct of the kidney is formed by two coats. The 
external is a dense, fibrous, and cellular tissue, but is destitute of 
any thing like muscle. The internal is a thin mucous lamina, w r hich 

* Amer. Med. Jour., Vol. iii. p. 442. 
f Anat. Atlas, Fig. 359. 



98 URINARY ORGANS. 

can be raised up without much difficulty, and is continuous, at its. 
lower end, with the internal coat of the bladder ; at the upper end, 
it is supposed by some anatomists to be reflected over the papilla?, 
and even to pass for some distance into the tubuli uriniferi. This 
duct has considerable powers of extension, as manifested by its 
transmitting large calculi from the kidney, and also, by its enormous 
enlargement in some cases of obstructed urethra ;* its sensibility is 
exquisite when irritated by a calculus passing down it. 

The walls of the tubuli uriniferi are the surface upon which the 
secretion of urine most probably takes place exclusively. The mu- 
cous membrane of the pelvis of the kidney being continued over them 
so as to form the surface; these canals, delicate as they are, exhibit 
an epithelium formed of nucleated cells. These cells, discovered by 
Henle, are close together without being angular; according to the phy- 
siological views of the case in all glands, they are the real elaborators 
of the urine, and upon becoming distended with it, they burst, and 
let out their contents into the tubuli uriniferi; being then decomposed 
a new generation of cells is produced from the nuclei of the extinct 
ones. They have to pass through the same series of changes, and 
thus it proceeds to the end of life. 

Corpora Wolffiana.] 

The Corpora Wolffiana, called after their discoverer, are small 
bodies found only in the earlier stages of fcetal life, one on each side 
in the lumbar region, and of which there are scarcely any traces at 
the end of the fifth month. When in full development, they are so 
large as to conceal the kidneys and the renal capsules, but as these 
latter organs grow, the corpora Wolffiana diminish, and are finally 
placed lower down. They are supposed to be vicarious kidneys for 
the time, and they consist in transverse coecal tubes, which are nu- 
merous. They have each an excretory duct, which leads from their 
lower part into the Sinus Uro-genitalis. 

The latter is also peculiar to the fcetal state, and is a tube which for 
the time receives from each side the ureter, the vas deferens, and the 
duct of the corpus Wolffianum ; and is prolonged into the urachus. 
The Sinus Uro-genitalis is finally divided into two branches, from 

* See Wistar Museum. 
f Anat. Atlas, Fig. 369. 



THE BLADDER. 99 

one of which is evolved the urinary bladder, and from the other the 
vesiculae seminales.* 



Of the Bladder, f 

The Bladder ( Vesica Urinaria,) is the reservoir for the urine, and 
is placed in the pelvis, just behind the symphysis of the pubes. 
When pressed upon, as it commonly is, by the adjacent viscera, it 
is flattened somewhat before and behind ; but removed from the 
body and inflated, it is an elongated sphere or an oval : the greatest 
diameter of which is vertical, in regard to the linea ileo-pectinea. 
The superior end of the bladder is called the upper fundus, and the 
lower end the inferior fundus : the latter is rather more obtuse than 
the other ; and between the two is the body. The neck of the blad- 
der is its place of junction with the urethra. The form of the bladder 
is influenced by age and by sex ; in very young infants it is cylin- 
droid, and owing to the smallness of the pelvis, rises up almost wholly 
into the abdomen. In the adult woman, who has frequently borne 
children, it is nearly spherical, has its greatest diameter transverse,^ 
and is more capacious than in man. 

The bladder is bounded in front by the pubes, above by the small 
intestine, behind by the rectum, and below by the prostate gland and 
the vesicula? seminales. From its superior end there proceeds to the 
umbilicus a long conical ligament, the urachus, which is placed be- 
tween the linea alba and the peritoneum, and produces a slight ele- 
vation or doubling of the latter. In mankind, the urachus is solid ; 
but some very rare cases are reported, in which it has been hollow, 
so as to permit the urine to flow through it from the bladder. This 
anomalous conformation has generally been attended with a con- 
genital obstruction of the urethra. § When the anterior parietes of 
the abdomen are put upon the stretch, a semi-lunar fold of the peri- 
toneum, as formerly mentioned, is seen to proceed, on either side of 
the urachus, from the lateral surface of the bladder almost to the um- 
bilicus. These folds contain, in their free edge, the fibrous remains 
of the umbilical arteries of the foetus, called subsequently to uterine 
life, the Round Ligaments of the bladder, though they have little or 

* Midler's Phys., p. 1639. 

| Anat. Atlas, Figs. 370 to 375, inclusive. 

X H. Cloquet, Anat. Descrip. 

§ Sabatier, Anat., vol. iii. p. 19. 



100 URINARY ORGANS. 

no influence on its position. The bladder is also fixed in its situation 
by the pelvic aponeurosis, a membrane elsewhere described with the 
organs of generation. 

The bladder consists of four coats : the Peritoneal, the Muscular, 
the Cellular, and the Mucous. 

The Peritoneal Coat is very imperfect, and is derived from the 
part of the peritoneum which descends from the anterior parietes of 
the abdomen into the pelvis. It covers the upper and the posterior 
face of the bladder, and then passes to the rectum, by sinking down 
between these two organs, so as to form the small pouch beneath the 
lower fundus of the bladder ; the apex of this pouch reaches within 
an inch of the base of the prostate. The upper margin of this pouch 
next to the bladder, forms a strong horizontal doubling, stretching 
across the pelvis, when the rectum is empty, and is on a level with 
the posterior end of the vesiculae seminales. Being connected to the 
subjacent muscular coat by a thin lamina of loose cellular membrane, 
the peritoneum may be dissected off without difficulty. In consi- 
derable distentions of the bladder, it is reflected from the upper end 
of the latter to the abdominal muscles in a line much above the 
pubes ; whereby a good opportunity is afforded of reaching, with an 
instrument, the cavity of the bladder without injuring the perito- 
neum. 

The Muscular Coat is of a thickness intermediate to that of the 
stomach and of the oesophagus, and its fibres are pale. They pass 
in very varied directions,* and are collected into flattened fasciculi, 
leaving interstices between them, through which the internal coat is 
occasionally caused to protrude, in strictures and other obstructions 
of the urethra. Many of these fasciculi, arise about the neck of the 
bladder, and ascending upwards, before, behind, and laterally, ter- 
minate at the superior fundus in the base of the urachus. Within 
these, which may be considered as the longitudinal fibres of the 
bladder, there are others forming a thinner lamina, whose course 
is transverse or oblique : they serve to connect the preceding. As 
the muscular fibres are collected at the neck of the bladder, and at 
the urachus, there is, of course, an increased thickness at these 
points. 

The Cellular Coat (Tunica propria) like that of the alimentary 

* Santorini, Septemd. Tabul. 



THE BLADDER. 101 

canal consists in a close, dense, lamellated, and filamentous cellular 
tissue, very extensible and difficult to tear. It is impervious to 
water, adheres closely to the muscular coat without, and to the 
mucous within, so as to form a strong bond of union between them. 
It is pervaded by many vessels and nerves, which it conveys to the 
mucous coat. 

The Mucous Coat is also called the villous, but is much more 
smooth than the corresponding one of the stomach. It is white, 
with a slight tinge of red, and abounds with mucous follicles, which 
though small and scarcely discernible in a natural state, are rendered 
very obvious by disease. It stretches with much facility, but like 
other mucous membranes, does not restore itself fully, and is rather 
thrown in the contracted state of the bladder, into wrinkles or folds, 
having a diversified course, and of a fugitive character, as they dis- 
appear again upon the next distention. It is very vascular. 

The internal face of this coat presents, at its inferior part, the fol- 
lowing appearances. 

1. The Vesical Triangle (Trigonus Lieutaudi, Trigone Vesicale,) 
is placed immediately behind and below the neck of the bladder, 
occupying the space between it and the orifices of the ureters. It is 
an equilateral triangle of an inch in length, its surface is smooth, 
is not affected very materially in extent either by the dilatation or the 
contraction of the bladder, and is elevated so as to be sufficiently 
distinct and well defined. 

2. The anterior angle of the triangle looks into the orifice of the 
urethra, and is generally so elevated that it has obtained the name 
of Uvula Vesicae; it is, however, simply a projection of the mucous 
membrane depending upon the subjacent third lobe of the prostate ; 
which, at this point, is not unfrequently much enlarged in the aged, 
and then presents a great difficulty in the introduction of a catheter. 

3. The Orifices of the ureters form the posterior angles of the 
triangle, and are contracted somewhat below the size of the canals 
themselves. They are said by Sir Charles Bell,* to be furnished, 
each one, with a small fasciculus of muscular fibres, which runs 
backwards from the orifice of the urethra, just beneath the lateral 

* Med. Chir. Trans. Vol-, iii. 
Vol II.— 10 



102 URINARY ORGANS. 

margins of the triangle, and, in its contraction, will stretch the ori- 
fice of the ureter so as to permit an easy passage of the urine into 
the bladder. The retrogradation of the urine is prevented by the 
ureter passing obliquely, for six or eight lines, between the muscular 
and the mucous coat; there is something also in the obliquity and 
elliptical shape, with a defined edge of the orifice itself which assists 
in this effect; as I have ascertained by removing the muscular coat 
entirely, at this point, and dissecting up the ureter, notwithstanding 
which, the bladder, when inflated, still retained its contents. Where 
the ureter penetrates the muscular coat, there is often found a layer 
of longitudinal muscular fibres ascending and enveloping it for half 
an inch, or an inch. 

4. The Inferior Fundus of the bladder (Bas-fond of the French) 
is a depression of the general concavity of the bladder, of about six 
lines in depth, placed between the base of the vesical triangle and 
the posterior side of the bladder. In the erect position, calculus, 
when present, lodges there. 

5. The Internal Orifice of the neck of the bladder resembles 
strongly that of a Florence flask, modified, however, by the projec- 
tion of the uvula vesica?, which makes it somewhat crescentic 
below. The neck of the bladder penetrates the prostate gland but, 
at its commencement, is surrounded by loose cellular tissue contain- 
ing a very large and abundant plexus of veins.* The internal layer 
of muscular fibres is here transverse; and they cross and intermix 
with each other in different directions, forming a close compact 
tissue, which has the effect of a particular apparatus for retaining 
the urine, and is called Musculus Sphincter Vesicas Urinaria. 
Generally, anatomists have not considered this structure as distinct 
from the muscular coat at large ; but the late Sir Charles Bell, Profes- 
sor in the University of Edinburgh, whose reputation as an anatomist 
was well established, gives the following account of it. 

" Begin the dissection by taking off the inner membrane of the 
bladder from around the orifice of the urethra. A set of fibres will 
be discovered, on the lower half of the orifice, which, being care- 
fully dissected, will be found to run in a semicircular form round 
the urethra. These fibres make a band of about half an inch in 

* Mascagni, Anat. Univ. Str. Prirn. Tab. Spec. Fig. V. 



THE BLADDER. 103 

breadth, particularly strong on the lower part of the opening, and, 
having mounted a little above the orifice, on each side, they dispose 
of a portion of their fibres in the substance of the bladder. A 
smaller and somewhat weaker set of fibres will be seen to complete 
their course, surrounding the orifice on the upper part; to these 
sphincter fibres a bridle is joined, which comes from the union of 
the muscles of the ureters."* 

After repeated observations on this point, I have come to the 
conclusion that Mr. Bell has indicated a real structure ; but my own 
dissections have resulted as follows : The inferior semicircumference 
of the neck of the bladder is defined by a thick fasciculus of mus- 
cular fibre, half an inch wide, running in a transverse direction, and 
having its ends attached to the lateral lobes of the Prostate Gland) 
being above the third lobe of the latter. This fasciculus is perfectly 
distinct from the ordinary muscular fibre of the bladder, and re- 
sembles in its texture the musculo-fibrous coat of the arteries. The 
superior semicircumference is also surrounded by a thin layer of 
muscular fibres of the ordinary kind, forming a broad, thin band of 
a crescentic shape, the lower ends of which are insensibly lost in 
the adjacent muscular coat of the bladder by being spread out. 
And, lastly, beneath the mucous membrane of the vesical triangle, 
there is a triangular muscle of the same size as the vesical triangle, 
Having elongated angles, the anterior angle may be traced to the 
posterior part of the caput gallinaginis, and the posterior angles to 
the orifices of the ureters and the adjacent part of the bladder. The 
texture of this muscle is, also, like that of the musculo-fibrous coat 
of the arteries. When a bladder is recent, this detail of structure 
is made out with difficulty : it requires to be previously hardened 
in spirits of wine. f That a power exists in the neck of the bladder 
of retaining completely the urine, has been satisfactorily demonstrated 
to me in a case of fistula in perineo, which was presented to the 
notice of the late Dr. Physick and myself, some years ago,! as 
well as in other cases occurring since then. The insertion of the 
muscle of the vesical triangle into the caput gallinaginis, has a 
double efTect, it by drawing the caput back fills up the front of the 
neck of the bladder; and by easing the orifices of the ductus ejacu- 

* Diseases of the Urethra, &c., p. 10. Lond. 1820. 

f Anat. Atlas, Fig. 373 from preparations in Anatomical Museum. 

£ Chapman's Med. and Phys. Journ. 1824. 



104 URINARY ORGANS. 

latorii allows a free exit of semen, while it prevents the latter from 
retrograding into the bladder. 

Occasionally there exist on each side of the neck of the bladder, 
passing from it to the pubes, a muscle of half an inch in breadth, 
the effect of which is to draw the neck of the bladder towards the 
symphysis pubis. This, called by some the muscle of Wilson, or 
the Compressor Urethrse has also an influence in retaining the urine. 
When it exists in a distinct state it is evidently, the anterior fasci- 
culus more detached than usual of the Levator Ani ; but under ordi- 
nary circumstances it appears as the anterior margin of that muscle, 
and therefore does not attract especial attention. 

As the urethra of the male performs the double office of conducting 
both semea and urine, it will be described more properly along with 
the organs of generation. 

The urine has a considerable number of constituents, the propor- 
tion of which varies according to age, health, and other circumstan- 
ces. Water forms about nine-tenths of it, the remainder is an animal 
matter insoluble in alcohol; uric and lactic acids; lactate of am- 
monia; sulphate of potash and of soda; hydrochlorate of soda and 
of ammonia ; phosphate of soda and of lime ; and fluate of lime. 



BOOK VI. 



ORGANS OF GENERATION. 



CHAPTER I. 

Of the Organs of Generation in the Male. 

The Male Organs of Generation consist in the Testicles and in 
the Penis, with their appendages ; or, in the language of some anato- 
mists, in the Formative and in the Copulative Organs ; which dis- 
tinction has been applied to both sexes. 



SECT. I. — OF THE PENIS.* 

The Penis, (Membrum Virile, Mentula,) from performing the two 
offices, one of which is the conducting of urine from the bladder, 
and the other the projection of semen into the female, has accord- 
ingly, a peculiarity of structure, which allows a state of collapse and 
of erection. Its shape is almost cylindrical, but terminating in front 
by an obtusely pointed extremity, named Glans. It adheres by its 
posterior end or root to the bones of the pelvis, at and below the 
symphysis pubis. 

It is formed by common integuments, by condensed cellular tissue,, 
by the Corpus Cavernosum, and by the Corpus Spongiosum. 

The skin on the penis is more thin and delicate than it is on most 
other parts of the body, and is furnished with a considerable number 
of sebaceous follicles or glands about the root of the organ, with 
hairs growing from the centre of them. This same skin, in passing 

* Anat. Atlas. Fig. 376 to 381, inclusive. 
10* 






J06 organs of generation. 

to the abdomen over the pubes, is somewhat protruded by a subja- 
cent deposite of; fat and cellular matter, causing an appearance cor- 
responding with the mons veneris of the female ; and is also generally 
thickly covered with short curly hair, which, as the individual ad- 
vances in life, proceeds in a pointed direction to the umbilicus. The 
skin of the penis is connected to the organ by a loose filamentous 
cellular substance, so that it slides readily backwards and forwards, 
and by its elasticity is well suited to the varying states of erection 
and collapse. At the anterior extremity it is thrown into a dupli- 
cature or fold, the prepuce, (Preeputium ;) the internal lamina of 
which being fixed circularly to the penis, some distance back from 
the point, permits a considerable portion of that extremity of the 
penis, called the Glans, to project when the prepuce is drawn back. 
The under middle part of the prepuce is attached to the extremity of 
the glans by a vertical longitudinal duplicature, called the Frsenum, 
which extends to the orifice of the urethra. 

The skin does not actually stop at the circumference of the glans, 
but is continued smoothly over it, modified, however, so much in 
its structure, as to be much more adherent, soft, delicate, vascular, 
and sentient: its cuticle there is a thin epithelium, readily separated 
by maceration. The projecting circular and oblique shoulder of the 
glans, behind which the skin becomes firmly joined to the penis, is 
called the Crown ( Corona Glandis. ) The contracted portion, behind 
the corona, is the Neck (Collum.) On the surface of the neck and 
the posterior face of the corona, the skin is furnished with an abun- 
dance of small glandular masses or follicles, (Glandulce Odoriferce 
Tysoni,) which secrete the thick white sebaceous matter, (Smegma 
prceputii,) that accumulates when personal cleanliness is not attend- 
ed to. 

The penis, in addition to other modes of attachment to the bones 
of the pelvis, is fixed by the Ligamentum Suspensorium. The latter 
i$ a triangular vertical fibrous lamina, which proceeds downwards 
from the symphysis pubes to the dorsum of the penis; and, accord- 
ing to Mr. Colles, envelops this organ to the glans, forming its cel- 
lular coat, and being continued into the fascia superficialis abdo- 
minis. This cellular coat is found sometimes in no small degree 
condensed in its texture and fibrous, so that it becomes a sort of 
fascia. Posteriorly, it is lost insensibly on the fascia of the thighs, 
covering the adductor muscles. At its origin it is occasionally 



THE PENIS. 107 

furnished with muscular fibres ; one strongly marked instance of 
which has been presented to me in my own dissections. 

The Corpus Cavernosum of the penis, forms by much the most 
considerable portion of the whole organ. Externally, it is a white 
fibrous membrane, of a dense structure, enjoying extensibility and 
an extreme degree of contractility. This coat of the penis is occa- 
sionally called its elastic ligament. Its external fibres pass, for the 
most part, longitudinally, except about the root, where they are 
blended with the periosteum of the bone, and with the tendons of 
the muscles. It arises by two conical crura, swollen at their base, 
from the internal face of the crura of the pubes and ischia, to within 
a little distance of the anterior part of the tuber ischii. At the lower 
part of the symphysis pubis these crura join and form a body ; which, 
when stripped of its connexions, resembles two cylinders united, 
lying alongside of each other; and which terminate in common, an- 
teriorly, by a truncated cone, covered obliquely by the glans. At 
the posterior part of the corpus cavernosum, in its centre, there is 
a septum, almost complete, also of the same elastic substance, which 
separates the two halves from each other; but, anteriorly, this septum 
is more imperfect, having an arrangement like the teeth of a comb, 
whence the term Septum Pectiniforme has been given it. This sep- 
tum is continued at its margins into a layer of circular fibres, con- 
stituting the internal coat of the corpus cavernosum. In this arrange- 
ment into external longitudinal and internal circular fibres, we see a 
renewal of the same mechanism which marks the hollow viscera. 
It is commonly not noticed by anatomists. 

In the middle of the corpus cavernosum, above, is a longitudinal 
depression for lodging the veins of the penis, and, in the same man- 
ner, there is another below, for the corpus spongiosum urethrse. 
The cavity of this membrane is filled by a spongy tissue, that arises 
from its internal face, and is formed of filaments and little laminae ; 
they, by crossing each other, make a multitude of cells, which have 
a perfectly free communication with one another, and generally are 
somewhat occupied by blood. A fine injection through the artery 
of the corpus cavernosum will fill these cells and return through 
the veins ; from which cause the cells may be considered as inter- 
mediate to the two orders of vessels. This opinion is the more 
probable from, the cells being lined, by a thin membrane like the in- 



108 ORGANS OF GENERATION. 

temal one of the veins, and which is easily seen near the septum by 
tearing the spongy part from it. 

The internal cellular structure of the corpus cavernosum is pro- 
bably formed, almost exclusively, by the internal coat of the dilated 
veins, partially sustained by the above filamentous and laminated 
bands, for the purpose of strengthening the arrangement. The ad- 
hesion of this structure at large to the corpus cavernosum is much 
weaker than one may suppose, as it is very easy to peel or roll it off 
almost without dissection, thus leaving the elastic ligament of the 
corpus cavernosum perfectly free. In the case of the corpus spon- 
giosum, the cellular structure, though analogous in texture to the 
above, does not peel off so easily. 

The Corpus Spongiosum Urethrse extends from ten or twelve lines 
behind the junction of the crura of the corpus cavernosum, to the 
anterior extremity of the penis. Externally, it has a coat resembling 
that of the corpus cavernosum, except that it is thinner, and in its 
centre is the canal for the passage of urine. Between the canal and 
the coat is a spongy structure, much finer than that of the corpus 
cavernosum, and though the cells communicate freely, still they have 
the appearance of convoluted veins. The corpus spongiosum is not 
of equal diameter in its whole course, for its commencement in the 
perineum, where it is pendulous, is enlarged into what is termed the 
Bulb ; from this it diminishes gradually to the anterior end, where 
it is again enlarged into the glans penis. 

Fig. 29. Muller* has made the assertion that there are two 

modes of arterial termination in this erectile or cel- 
lular structure of the penis, one by direct connexion 
with the incipient ramuscles of the veins, and the 
other, by tufts of cceca bent backwards on them- 
selves, as here represented, and, which he has named 
Helicine arteries (Arter. Helicime.) Projecting as they do into the 

* Elem. Physiol, vol. i., p. 252. Lond., 1840. 

Prof. Valentin (Mailer's Archiv. 1838. p. 182) denies the existence of the 
arteriae helicinae. According to his observation all the branches of the arteries 
of the corpus cavernosum, after forming numerous anastomoses terminate in 
the large veins of the penis. The small arteries run in the centre of the bundles 
of fibres which lie between the veins ; and when these bundles of fibres, or 
band-like septa, are cut or torn across, they, together with the arterial twigs 
within them, contract and assume a contorted, sometimes 6piral figure. In 




THE PENIS. 109 

venous cells, he declares that though no openings from them can be 
discovered, yet the latter exist so as to fill the cells in erection. 
These singular arteries are found principally in the back part of the 
corpus cavernosum and spongiosum, and are seen after a minute 
size injection of the arteries of the penis, by washing the size from 
the cells, when the cells have been filled. 

The Urethra is a mucous canal, whose length varies according to 
the degree of erection in the penis, and extends from the neck of the 
bladder to the extremity of the glans. It is difficult to assign a 
fixed length to the canal of the urethra, owing to the variable size 
of the penis in different persons, and in the same individual, depend- 
ing upon his general vigour and alsoperiod of life. The measurements 
of Professor Pancoast* in the black and mulatto, show an average of 
about seven inches from the neck of the bladder to the end of the 
urethra in the unstretched state, and about an inch more in stretch- 
ing the organ moderately. It is, however, well known that the 
sexual organs of the black are larger, both male and female, than of 
the white. 

The urethra is curved, and receives in its course the ductus 
ejaculatorii, the excretory ducts of Couper's glands, and the mucous 
lacunae of its own internal membrane. The first part of this canal 
which traverses the prostate gland is from fifteen to eighteen lines 
in length, and is called the Prostatic Portion : it is well supported by 
this body, although its own sides are very thin. On its inferior sur-. 
face is the doubling which constitutes the Verumontanum or Caput 
Gallinaginis. On either side of the caput gallinaginis the canal of the 
urethra is depressed into something like an oblong cul-de-sac or 
narrow trench, where are to be found the lacuna? of the prostate 
gland. 

Between the Prostate and the Bulb is the membranous part of the 
urethra, about eight or ten lines long ; it is unprotected, except by 

this stite they form the so-called arteriae helicina?. The fibrous bands which 
pass inwards between the anastomosing veins from the external tunic of the 
corpus cavernosum, consist, according to Prof. Valentin, of tendinous tissue, 
and give attachment to muscular fibres, similar to those of the intestinal canal, 
which pass from them to the parietes of the veins. M. Valentin supposes erec- 
tion to be in a great measure due to the active dilatation of the veins by these 
muscular fibres ; but the characters on which he founds his belief that the 
fibres in question are muscular, are not conclusive. 
* Wistar's Anat. 8th Edit., vol., ii. p> 17Q. 



110 ORGANS OF GENERATION. 

a soft covering, which seems in some measure to be a mixture oi 
gelatinous matter and muscular fibre. The former was considered 
by Littre as a glandular body which secreted a viscid humour into 
the interior of the canal ; the latter, probablv, is the part described 
by Winslow as the inferior prostatic muscle ; which he asserted to 
arise on each side of the membranous part of the urethra, and to be 
inserted into the corresponding branch of the pubes near the sym- 
physis. The membranous part of the urethra does not get into the 
end of the bulb but penetrates it from above, half an inch or more 
occasionally, from its extremity, just below the junction of the crura 
of the corpus cavernosum. 

The canal varies in its diameters: at its commencement, which is 
synonymous with the neck of the bladder, it is large ; it then con- 
tracts at the back of the caput gallinaginis, and immediately en- 
larges in the fore part of the prostate, at the sides of the caput. 
The membranous part is small ; the canal then enlarges in the bulb. 
In the body of the penis the canal is successively diminished, till it 
comes almost to the glans, when it is so remarkably enlarged again 
as to get the name of Fossa Navicularis ; it terminates, finally, by a 
short vertical slit at the extremity of the glans. 

The canal of the urethra is formed of a very thin mucous mem- 
brane, on the outside of which is a dense filamentous cellular sub- 
stance possessing much extensibility, contractility and elasticity. 
The mucous membrane has great vascularity, and its veins are so 
superficial that they frequently bleed freely upon the introduction of 
an instrument into the bladder, it is also very sensitive. The cel- 
lular coat on its outside, whereby it adheres to the spongy structure, 
contracts sometimes in such a manner that circular fasciculated 
ridges simulating the presence of circular muscular fibres, are seen 
shining through the mucous coat, though when the mucous coat is 
peeled off this arrangement disappears. 

In the whole length of the canal there are two folds or lines, one 
above, and the other below ; and in the membranous and spongy 
portions, excepting the fossa navicularis, longitudinal folds of the 
mucous membrane also exist, which are effaced by distention. 
The fossa navicularis sometimes exhibits in the contracted penis, 
hardened in spirits of wine, very superficial folds of the mucous 
membrane almost transverse, in the narrow depressions between 
which we see the orifices of very fine mucous follicles. 

In the upper part of the canal there are a great many mucous 



THE PENIS. Ill 

lacunae ;* Loder has marked about sixty-five : there is one parti- 
cularly large in the upper surface of the fossa naviculars, which, it 
is said, has stopped the point of a bougie, and been mistaken for 
stricture, f 

Mr. Shaw has described a set of vessels immediately on the out- 
side of the internal membrane of the urethra ; which when empty, 
are very similar in appearance to muscular fibres. He says, he has 
discovered that these vessels form an internal spongy body, which 
passes down to the membranous part of the urethra, and forms even 
a small bulb there. J His preparation, being a quicksilver injection 
of the part, is certainly a very satisfactory demonstration of its exist- 
ence ; yet in my own observations, where the blow-pipe has been 
resorted to, it has rather appeared to me to be the cellular membrane 
connecting the canal of the urethra with the corpus spongiosum. 

The arteries of the penis come from the internal pudic; some of 
its veins follow the course of the arteries, and others collect into the 
two venae dorsales penis ; the nerves come from the Superior and 
Inferior Pudendal. 



SECT. II. — OF THE MUCOUS GLANDS AND APPARATUS. 

The Seminal Vesicles§ (Vesiculce Seminales) are two convoluted 
tubes, one on each side, two inches in length, placed on the lower 
fundus of the bladder, between it and the rectum, and behind the 
prostate gland. At their anterior extremities they approach very 
nearly to each other, being only separated by the intervention of 
the vasa deferentia. They are fixed to the bladder, and surrounded 
by a thick mass of adipose and cellular matter, with many blood 
vessels, principally veins, passing through it. 

When inflated and dried, they present the semblance of cells, 
but are, in fact, long tubes; which being convoluted, are reduced 
to the apparent dimensions mentioned. When dissected and 

* Tabula Anat. 

f Sir Everard Home formerly communicated to the Royal Society a highly 
interesting paper on the structure of the lining membrane of the urethra. From 
his microscopical observations he was induced to think that it is muscular. 

X Med. Chir. Trans, vol. x. 

§ Anat. Atlas, Figs. 383, 390, 391, 392. 



112 ORGANS OF GENERATION. 

stretched out, they are four or five inches long, by three lines in 
diameter. 

There are also several pouches on each side of the long tube 
which increase the number of cells. The convolutions are pre- 
served by the intermediate cellular tissue. These bodies consist of 
two coats: an external, which is a condensed fibro-cellular sub- 
stance; and an internal, which is mucous, being a continuation of 
the lining membrane of the urethra. The excretory duct of each 
vesicle is about a line and a half long, when it joins in the sub- 
stance of the prostate with the vas deferens of the same side ; a 
common canal {ductus ejaculatorius) is thus formed, which runs 
parallel with its fellow, below the urethra.* 

The Ductus Ejaculatorius is about eight or ten lines long, and 
opens by an oblong orifice, on the anterior margin of the Caput 
Gallinaginis; it is larger behind than before, which gives it a conical 
shape, and allows fluids injected to pass freely from the vas deferens 
to the vesicula seminalis, and the reverse. 

The vesiculse are commonly filled by a drab-coloured thick fluid, 
supposed to be a mixture of the semen, with their own proper se- 
cretion, though, of this, Mr. Hunterf doubted, inasmuch as he found 
them equally well filled in cases where the testicle of the corres- 
ponding side had been lost, and therefore he concluded that they 
were not indebted to the secretion of the testicle for their contents. 
The discovery, latterly, of spermatic animalcules in the fluid con- 
tained after death in the vesiculae is considered now as proof surfi- 
cient of their being reservoirs of the male semen along with their 
own secretion, as these animalcules Were most probably conveyed 
there along with the semen. 

The Prostate Gland (Glandula Parastata) is a body about the 
size and form of a horse chestnut, fixed on the neck of the bladder, 
and penetrated by the urethra, which traverses it much nearer its 
superior than its inferior surface. The base of it is turned back- 
wards, and the point upwards; its inferior surface rests upon the 

* In a dissection executed at the University by Dr. Joseph Togno, a muscle 
was found on the inferior surface of the seminal vesicles arising from the pros- 
tate gland, and inserted into them. This is said to be a common arrangement 
in some animals. 

f Observations on the Animal Economy. 



PROSTATE GLAND. 113 

rectum ; it is rendered concave by that circumstance, and its sides, 
in the distentions of this organ by faeces, are overlapped by it. The 
Prostate has, posteriorly, a notch in its centre, which divides it into 
two lateral lobes, and by raising the Vesiculse Seminales, we see 
where their excretory ducts penetrate the gland, and separate from 
the body of it, the little tubercle, to which Sir Everard Home* has 
particularly called the attention of the profession, and considered 
as a third Lobe ; it being certain that it is frequently the seat of dis- 
ease and tumefaction. 

On the under surface of the canal formed in the prostate, by the 
urethra, is, as mentioned, the oblong elevation called the Verumon- 
tanum, or Caput Gallinaginis. It commences a little in front of the 
uvula vesicae, and, being broader and higher behind, comes to a 
point very gradually before; it is about eight or ten lines long. 
Along the posterior part of this ridge a long cleft is sometimes 
found, it being the orifice of a lacuna, first observed by Morgagni ; 
and in front are the orifices, bordering upon each other, of the ductus 
ejaculatorii. Very superficial folds of the lining membrane, some 
three or four in number, radiate from the anterior end of the caput 
to the anterior end of the membranous portion of the urethra. The 
use of the Caput Gallinaginis, as already intimated, is probably to 
plug the orifice of the urethra at the neck of the bladder, at the 
moment of ejecting the semen: it being drawn backwards to that 
effect by the muscle of the vesical triangle. 

The prostate consists in a condensed, white, extensible, though 
easily lacerated fibrous cellular tissue, within which are placed a 
great number of mucous canals, that have from eight to twelve 
ducts, or, according to Loder, from thirty-two to forty-four, passing 
obliquely forwards, and terminating in the urethra, as stated, at the 
sides of the urethral crest, or caput gallinaginis. It is an aggrega- 
tion of smaller glands, like the mamma or any other composite 
gland ; the principal ducts are, therefore, formed by the convergence 
of branches in successive junction. The fluid secreted is thick, 
ropy, white, and semi-transparent, in a healthy state. The prostate 
is surrounded by a fibrous capsule, to be described. 

The lacunas of the third lobe penetrate the coats of the bladder, 
behind the caput gallinaginis. 

* Diseases of Prostate. 

Vol. II.— 11 



114 ORGANS OF GENERATION-. 

Of the Glands of Couper.— These glands are also intended for 
the secretion of mucus, or a fluid very much like it, into the canal 
of the urethra. They are two in number, one on each side, and 
are situated in advance of the prostate, between the lamina? of the 
triangular ligament, at the point where the bulb of the urethra ad- 
heres to it. Commonly, they are about the size of a garden pea, 
but not unfrequently much smaller, and, in some instances, cannot 
be found at all, which induced Hiester to declare, that he had 
searched for them fruitlessly. They are yellowish, hard, and con- 
sist of several lobules united together. Each one has an excretory 
duct, that receives readily a bristle, and passes obliquely forwards, 
between the corpus spongiosum and the canal of the urethra, to ter- 
minate in an oblique orifice in the latter, about an inch distant from 
the gland. 

One or more glands, of the same description, and discovered by 
Littre, are occasionally found just in front of Couper's. They also 
discharge their secretion into the adjacent part of the urethra. In 
my own dissections I have not met with them. 



SECT. III. — OF THE TESTICLES.* 

The Testicles ( Testes, Didymi) are two in number, one for each 
side of the scrotum. Being the seat of the secretion of sperm or 
the male prolific liquor, their function is of the first importance in 
the act of generation. They are of an oblong oval form, somewhat 
compressed laterally ; and present their edges forward and back- 
ward. From being suspended near the middle of their posterior 
edge by the spermatic cord, the upper end points somewhat forward, 
while the lower one is directed in the same degree backward. They 
are about an inch and a half long, by one inch in breadth, and eight 
or nine lines in thickness. They are of equal size generally, but in 
case of a difference it is in favour of the right ; the latter is also re- 
markable for being suspended higher than the left, a feature in ancient 
statuary, so universal, as to prove the vigilance and accuracy of the 
sculptors of those days, in regard to the proportions and peculiarities 
of the human form. " Two obvious advantages attend this arrange- 
ment: one, that of [the testicles passing each other without col- 

* Anat. Atlas, Figs. 386 to 395, inclusive. 



THE TESTICLES. 115 

lision when the thighs are brought together ; and another, the facility 
of keeping the penis to one side, instead of straight forward in the 
middle line of the body."* 

The testicle is enveloped by several tunics ; they are the Scrotum, 
the Dartos, the Tunica Vaginalis, and the Tunica Albuginea. 

The Scrotum is merely a continuation of the common skin from 
the inner side of the thighs, the perineum, and the penis, and is 
common to the two testicles. It is a symmetrical bag, and the two 
halves are marked off from each other by a middle line or elevation 
of the skin, called the Raphe, w T hich begins in the perineum at the 
anus, and, winding around the scrotum, is continued along the under 
surface of the penis to the prepuce. 

The skin of the scrotum is thin, darker than elsewhere, but has 
a thick, strong epidermis; it has many sebaceous follicles in it, 
and is sparingly furnished with hair. It is very extensible, as 
manifested in fatigue, and by hydrocele ; and may be contracted 
again so as to draw the testicles close under the pubes, though for 
the latter power it principally depends upon the subjacent coat. 
Its surface is covered with wrinkles, for the most part transverse, 
and ending at the raphe : they are effaced during its great dis- 
tentions in hernia and dropsy, and then it has a smooth shining 
surface. 

The Dartos is placed within the scrotum, and forms two distinct 
sacs or tunics, one for each testicle. It arises from the inferior 
margins of the crura of the ischia and of the pubes, and lines the 
scrotum till it reaches the raphe ; it is then reflected upwards to 
form the partition between the testicles, [septum scroti,) and ter- 
minates at the corpus spongiosum urethrae. This membrane, ac- 
cording to the observations of MM. Chaussier, Lobstein, and 
Breschet,! does not exist in the scrotum till the descent of the tes- 
ticle, and then appears to be an expansion of the gubernaculum 
testis. 

It receives a considerable number of blood vessels, which, owing 
to the thinness of the skin, may be seen in the living body, ramify- 
ing through its substance: its general appearance is, therefore. 

* Sir A. Cooper on the Testis. 1830. 

f Dictionnaire des Sciences Med., tome viii. 



116 ORGAN'S OF GENERATION. 

reddish. It is destitute of fat, and consists in long fibres much 
matted together, and passing in every direction : they are easily 
separated by distention with air or water, and by slight maceration. 
Its powers of contraction are exceedingly well marked upon the 
application of cold to the scrotum, from which cause it has been 
considered by many anatomists as muscular : the only distinct evi- 
dence, however, which I have met with of a resemblance to the 
latter, has been found generally on its posterior face, near the 
perineum.* From its equivocal character, J. F. Meckel has very 
ingeniously suggested that it forms the transition from cellular to 
muscular tissue, and that there exists between it and other muscles 
the same relation that there is between the muscles of the superior 
and of the inferior orders of animals. Among the latter, the fibrous 
structure is indistinctly marked, and is masked by gelatine, c an ele- 
ment of the cellular tissue ; which envelops and conceals the fibrine, 
an element of the muscular tissue. 

The fibres of the cremaster muscle, which are next in order, 
form a very imperfect covering to the testicle, and belong rather 
to the spermatic cord: what remains to be said concerning them 
will be more properly introduced into the account of the latter. 
The cellular substance that connects the dartos and the cremaster 
with the tunica vaginalis forms a compact and perfect lamina, 
sometimes spoken of as the Tunica Vaginalis Communis Testis. 
There is one for each testicle, which it surrounds entirely, as well 
as its chord, and connects the chord to the margin of the external 
abdominal ring, as stated in the account of the latter. At its upper 
end it is continuous with the cellular substance that unites the peri- 
toneum to the parietes of the abdomen, as may be proved by in- 
flating it, when the air will penetrate accordingly through the ab- 
dominal canal. 

The Peritestis, or Tunica Vaginalis, was originally a process of 
peritoneum, communicating with the cavity of the latter through 
the abdominal canal; but in the adult, it appears as a complete 
and distinct sac. As it is very rigidly comparable to a double 
night-cap drawn over the head, we accordingly find that the testi- 

* Since the first edition, I have dissected one subject, (January, 1830,) 
where the fibres were evidently muscular, though interwoven. 



THE TESTICLES. 117 

cle, along with the epididymis is pushed into it from behind. That 
portion of the tunica vaginalis which is in contact with the testicle, 
or rather with the tunica albuginea, adheres so closely that it can- 
not be separated, except very partially and in shreds; but it may 
be detached easily from the epididymis, with the convolutions of 
which it is in immediate contact. This sac is longer and larger 
than the testicle itself, from which cause it ascends for several lines 
above the superior end of the gland, and the free part hangs loosely 
about it. Its cavity may, with but little force, be injected so as to 
hold an ounce or two of fluid. 

This membrane is smooth and polished on the surface forming 
its cavity, and contains a small quantity of serous halitus, which 
allows the opposed surfaces to glide freely upon one another. Its 
exterior connexion with the dartos is so slight that it may be with- 
drawn without dissection, with the exception of an adhesion at the 
lower end of the testis arising from the remains of the guberna- 
culum : in such case, however, it still continues to be invested by 
the tunica vaginalis communis, from which it can only be removed 
by a special dissection. 

The Tunica Albuginea is the proper coat of the testicle; is in im- 
mediate contact with its glandular structure, and serves to maintain 
its shape, as well as to protect it from pressure. From its internal 
surface proceed many membranous, horizontal fibres, which form 
partial partitions of its cavity (Septula Testis) and incline towards 
its posterior part, where they terminate in a longitudinal projection, 
called Corpus Highmorianum. The latter is of a prismatic shape, 
somewhat broader above than below, and is of but little consequence, 
except that it was once erroneously supposed to be a sinus, into 
which the seminiferous tubes discharged. Sir Astley Cooper pro- 
poses to call this the mediastinum testis, and considers the Corpus 
Highmorianum as being formed by an inflection of the tunica albu- 
ginea. The Septulse Testis, he asserts, really envelop the semini- 
ferous tubes, by forming bags which support, confine, protect, and 
nourish the tubular structure of the testis.* The albuginea is per- 
forated by several foramina along its posterior margin, where there 
is a deficiency of tunica vaginalis, for the passing of excretory ducts 
and blood vessels. 

* Observations, &c. on the Testis, p. 14. London, 1830. 

11 * 



118 ORGANS OF GENERATION. 

This membrane is dense, strong, white, and fibrous, resembling 
in structure the tunica sclerotica of the eye, and the dura mater of 
the brain. Sir A. Cooper considers the tunica albuginea as con- 
sisting of two layers which can be readily separated by dissection, 
excepting in front; the outer layer is the fibrous one, while the in- 
ternal one, which he calls Tunica Vasculosa, has the spermatic 
arteries and veins ramifying upon it. They are rendered very dis- 
tinct from each other by a minute injection.* 

Of the Minute Structure of the Testicle.]— The glandular portion 
of the testicle consists in a congeries of zig-zag tubes {Tubuli Semi- 
niferi) which are collected into lobules. One, two, or more tubes 
constitute a lobule, and the lobules are kept apart by the septula? 
testis. These lobules are of a conoidal shape, having their points 
towards the posterior middle line of the Testis and their bases 
rounded, they diverge from the corpus Highraorianum, so as to fill 
up the cavity of the tunica albuginea. The entire number of tubes 
amounts to 300, according to Dr. Munro; with an aggregate length 
of 5208 feet, and the diameter of each one does not exceed one two- 
hundreth part of an inch, and its length is somewhat short of seven- 
teen and a-half feet. Their number is, according to Krause, from 
404 to 484. Lauth has stated the number of tubes to be 840, and 
the length of each to be about twenty-seven inches, which corres- 
ponds nearer with my own observations, and makes an aggregate 
length of about one-third of that represented by Dr. Munro. These 
tubes form convolutions or hanks, the threads of which are serpen- 
tine, very much like the thread of a ravelled stocking; and are held 
together by a delicate cellular substance easily softened by macera- 
tion. Each tube forms of itself a hank, which is kept distinct from 
the adjacent ones by the septula? or processes of the albuginea, and 
may be easily picked out from them. Their extreme tenuity and 
delicacy of structure cause them, when well macerated, drawn out 
with a pin, and then suspended in water, to resemble a tangled 
skein of fine silk. 

The tubuli seminiferi finally terminate in some straight tubes, 
called the Vasa Recta, which unite near the middle back part of 
the testicle in a somewhat complicated arrangement, obtaining the 

* Observations, &c. on the Testis, p. 14. London. 1830. 

| Hunter, Med. Comment, p. 1. 1777. Albinus, Acad. Annot. Lib. ii. 

Loder, Tab. Anat.— Ruysch, Thes. Anat. iv. Haller, Op. Min. torn, ii.— Alex. 
Munro. de Testibus, Ed. 1755. 



THE TESTICLES. 119 

name of the Rete Vasculosum Testis. This Rete Vaseulosum is 
placed in the Corpus Highraorianum and from it there proceed from 
twelve to eighteen ducts (Vasa Efferentia) which go upwards and 
backwards through the corpus Highmorianum and the tunica albu- 
ginea. Each of these vasa efferentia is then convoluted upon itself 
into a conical body, called Conus Vasculosus, which presents its 
base backwards. Each conus, at its base, has its tube entering 
successively into the tube of which the Epididymis is formed. 

Notwithstanding the extreme tenuity of these several arrange- 
ments in the excretory ducts of the testicle, they may be entirely 
filled with quicksilver from the vas deferens; but the task is one of 
great difficulty, and rarely succeeds. 

The anterior ends of the tubuli seminiferi would seem from the 
observations of Lauth and Krause,* to have different modes of ter- 
minating, some end by cceca, others by a loop, and others by anas- 
tomosis with contiguous tubes. These anastomoses according to 
Lauth, are most frequent towards the base of the lobules, and occur 
there about every three inches. 

At the other end of the seminal tubes, several unite into one, to 
form a vas rectum, of which there are at least twenty, and with a 
diameter larger than the tubuli seminiferi. The vasa recta are a 
line or two long, they then are reduced into from seven to thirteen 
trunks, forming what is called the Rete Vasculosum Testis, which is 
distinguished by the waving course of its trunks, and by their fre- 
quent anastomoses with each other. 

According to Lauth, the number of vasa efferentia varies, in diffe- 
rent subjects, from nine to thirty, and when the entire length of each 
one is extended it measures eight inches ; of course, including the 
conus Vasculosus. 

The Epididymis is the prismatic arch which rests vertically on 
the back of the testicle, and adheres to it by the reflection of the 
tunica vaginalis. It is enlarged at both ends, the upper of which, 
being formed by the Coni Vasculosi is called the Globus Major, and 
the lower enlargement is the Globus Minor. It is made of a single 
convoluted tube, of the fourth of a line in diameter. After this tube 
has got to the lower end of the globus minor it becomes less con- 
voluted, enlarges, turns upwards on the inner side of the epididymis, 
and obtains the name of Vas Deferens, which before it reaches the 
top of the epididymis has become perfectly straight, or almost so. 

* Miiller, loc. cit.p. 499. 



120 ORGANS OF GENERATION. 

The average length of the canal of the Epididymis is about twenty- 
one feet, and the coni vasculosi discharge into it at intervals of three 
inches and a-quarter.* 

There is a blind duct, (Vasculum Aberrant) which begins at the 
top of the epididymis and terminates below ; the base of it is up- 
wards, and the other end discharges into the lower end of the ca- 
nal of the epididymis, where the latter makes its turn into the vas 
deferens. Its length varies from one and a half to fourteen inches. 
Sometimes there are several. The use is unknown. 

The tubuli seminiferi form a system of closed tubes, with the ex- 
ception of the posterior end, which discharges into the Rete Testis. 
Their diameter being about fifteen times greater than that of the 
arteries ramifying upon them, the conclusion is drawn that their 
whole internal surface executes the seminiferous secretion. 



Of the Spermatic Chord. 

The Spermatic Chord is a fasciculus of about half an inch in dia- 
meter, which may be felt very readily through the skin of the scro- 
tum, passing from the upper end of the testicle to the external ab- 
dominal ring. It is formed by the Vas Deferens ; the Spermatic 
Artery and Veins ; the Lymphatics of the Testicle ; and the Nerves ; 
all being covered in by the Tunica Vaginalis Communis, and by the 
Cremaster Muscle. 

The Cremaster Muscle, also called the tunica elythroides,f being 
derived from the internal oblique and the transverse muscle of the 
abdomen,:}: forms a very complete envelope to the chord from the 
abdominal ring to the testicle. But when it reaches the latter its 
fibres spread out and become indistinct upon the tunica vaginalis 
communis, as they there consist in small, pale, scattered fasciculi ; 
many of which terminate insensibly, while others form on the front 
of the tunica vaginalis loops, having their convexities downwards. 
This muscle draws the testicle upwards, an action very different 
from the corrugation of the scrotum. 

The Vas Deferens, or the proper excretory duct of the testicle, is 
a white tube of about a line and a half in diameter, and has a car- 

* Lauth, see Muller. f EWg«, a sheath. % See Abdominal Muscles 



THE TESTICLES. 121 

tilaginous feel. Its parietes are thick, as its cavity will not receive 
a body larger than a bristle, without being put upon the stretch. It 
traverses a long space, and in doing so, first passes at the back of 
the chord from its commencement to the internal abdominal ring : 
having reached the latter, it then abandons the spermatic artery and 
vein, and dipping into the pelvis, by the side of the bladder, goes 
between the lower fundus of the latter and the ureter. It then con- 
verges towards its fellow, along the under extremity of the bladder, 
at the inner margin of the vesicula seminalis of the same side, and 
finally terminates in the urethra near the neck of the bladder, by 
forming the Ductus Ejaculatorius with the assistance of the duct of 
the adjoining vesicula seminalis. About two and a half inches from 
its termination, it enlarges and becomes somewhat tortuous. 

This duct consists of two coats : the external one is hard, compact, 
and occasionally fibres are seen in it ; but its structure is not very 
evident, and is peculiar. The internal is a mucous membrane. 

For the description of the remaining portions of the chord, see 
Spermatic Artery, Vein, Lymphatics, and Plexus of Nerves. 

The Testicles undergo a remarkable change in their position, 
from the earliest development of their rudiments to the perfect fcetal 
state. They are not formed in the scrotum, but in the abdomen just 
below the kidneys ; from which position they are gradually trans- 
ferred. About the middle of the third month of gestation they are 
two lines long, and placed behind the peritoneum, to which they 
loosely adhere. The vas deferens then, instead of rising up on the 
side of the epididymis, goes straight down into the pelvis. At this 
period may be seen the gubernaculum testis, discovered by J. 
Hunter,* which becomes more distinct in a few weeks afterwards, 
and assumes a triangular appearance. This gubernaculum has the 
office of drawing the testicle down into the scrotum ; its point com- 
mences in the upper part of the latter, somewhat below the external 
abdominal ring ; it passes through the abdominal canal, ascends 
upon the iliacus internus muscle, and is attached by its base to the 
inferior end of the testicle. In front of the gubernaculum, a pro- 
cess, or small pouch of peritoneum, passes through the abdominal 
canal to the upper part of the scrotum. By the contraction of the 
gubernaculum, the testicle is brought, about the seventh or eighth 

* Med. Cororaent. Lond.. 1777. 



122 ORGANS OF GENERATION. 

month, into the scrotum, by sliding down behind the pouch. The 
lower end of the pouch, at which the testicle is finally arrested, be- 
comes the tunica vaginalis testis. 

As soon as the testicle has reached the scrotum, the neck of the 
pouch has a tendency to close and to become obliterated, which is 
commonly accomplished at the period of birth ; yet it sometimes 
remains open for a longer time and becomes the occasion of con- 
genital hernia. Very generally at birth, the orifice of the pouch will 
receive the end of a probe to the depth of a line or two ; but all 
below is perfectly closed, and has its structure so condensed and 
altered, that no one, from a view of it alone, would suppose that 
the cavity of the tunica vaginalis had ever communicated with that 
of the peritoneum.* 



SECT. IV. — OF THE MUSCLES AND FASCL/E OF THE 
PERINEUM. f 

Perineal Fascia. 

The Perineal Fascia is placed just beneath the skin of the peri- 
neum, and covers the muscles. It is spread over nearly all the 
space between the anus and the posterior margin of the scrotum, 
and between the rami of the pubes and the ischia on each side : it 
is very firmly fixed to these bones, and is gradually blended with 
the cellular substance of the posterior part of the scrotum. This 
fascia is rather thin, but, in case of a rupture of the posterior part of 
the urethra, prevents the urine from showing itself in the perineum, 
and drives it into the cellular structure of the scrotum. In abscesses 
of the perineum, it also prevents the fluctuation from being very 
evident. 

* The explanations and anatomy of this process have been treated at large 
in the following works : 

Girardi, Tabul. II. adj. Septemd. Tab. Santorini. 

J. Hunter, Observations on certain parts of the Animal Economy. W. 
Hunter, Med. Commentaries. 

Edwardi Standifort, Opusc. Anat. 

Wrisberg. Comment. Medic. Physiolog., &c. 

f Anat. Atlas, Figs. 384, 385. 



MUSCLES AND FASCIJE OF THE PERINEUM. 123 

The Musculus Erector Penis. 

It is so situated, as to cover the whole of the crus of the penis 
which is not in contact with the bony margin, of the pelvis. It 
arises, therefore, tendinous and fleshy, from the anterior part of the 
tuber ischii ; its fleshy fibres adhere to the internal and external mar- 
gins of the ramus of the ischium, and of the pubes, and proceed 
upwards : just before the union of the crura of the penis, they end 
in a flat tendon which is lost on the side of the corpus cavernosum 
of the penis.* 

Its use is not well understood. 



The Musculus Accelerator Urince, 

Lies on the bulb and back part of the corpus spongiosum urethrse ; 
it is a thin muscle, consisting of oblique fibres. 

It arises by a pointed production from the side of the body of the 
penis ; its origin is continued obliquely across the inferior surface of 
the crus penis, where the latter begins to form the body of the penis. 
It arises, also, for an inch from the inner side of the ramus of the 
pubes, between the crus penis and the triangular ligament of the 
urethra. The muscles of the opposite sides are inserted into one 
another by a white line, which marks the middle of the bulb of the 
urethra ; and by a point, into the anterior extremity of the sphincter 
ani, where they are joined by the transversi perinei. 

In order to see the origin of these muscles very distinctly, sepa- 
rate them from each other in the middle line, and dissect them 
from the corpus spongiosum. Cut transversely through the corpus 
spongiosum about three inches before the triangular ligament, and 
dissect it clearly from the corpus cavernosum, turning it down- 
wards so that it may hang by the membranous part of the urethra. 
By putting the two acceleratores on the stretch, it will be seen that 
besides the origins mentioned, they arise, also, from each other by 
a tendinous membrane that is interposed between the corpus spon- 
giosum and cavernosum ; so that they literally surround the back 

* The late Dr. Lawrence informed me that he had frequently found mus- 
cular fibres between the bone and the crus penis. 



124 ORGANS OF GENERATION. 

part of the urethra, constituting a complete sphincter muscle for 
it. This account of the accelerator urinae being peculiar to my- 
self, is adopted from a strong analogy between it and the sphincter 
vaginae. 

The two muscles are considered by M. Chaussier as forming but 
one : in that case its origin will be reversed, and commence in the 
middle line of the perineum instead of terminating there. As this 
muscle, and the erector penis, touch by their contiguous faces, it is 
difficult to get into the membranous part of the urethra in lith- 
otomy without cutting through the muscular fibres of one or the 
other. 

It propels the urine and semen forward. 



The Musculus Transversalis Perinei, 

As its name implies, passes directly across the perineum ; it arises 
from the inner side of the ischium, just at the origin of the erec- 
tor penis, and is inserted where the sphincter ani and acceleratores 
urinse join. 

I have observed that when the lower part of the accelerator was 
extended much below its usual line, and strongly developed, that 
the transversalis was very irregular in its origin and course ; consist- 
ing frequently of a few fibres which did not deserve the name of a 
distinct muscle, and lying almost unappropriated in the adipose 
matter of the part. 

Occasionally, a fasciculus of muscular fibres exists, called, by 
Albinus, Transversus Perinei Alter, which arises in front of the 
transversalis : it seems generally to be a loose fasciculus of the ac- 
celerator urinse muscle, and is inserted into the perineal junction 
just behind it. 

The use of these muscles seems to be to contribute to fix the bulb 
of the urethra. 



The Musculus Sphincter Ani, 

Consists in a plane an inch thick, of elliptical fibres immediately 
beneath the skin of the anus, and which surrounds the latter in order 



MUSCLES AND FASCI^ OF THE PERINEUM. 125 

to keep it closed. The long diameter of the ellipsis is extended 
from the coccyx towards the symphysis pubes, and has its angles 
very much elongated ; the anterior may be traced terminating insen- 
sibly in the posterior face of the scrotum. It has two fixed points, 
the last bone oftheos coccygis behind, and the perineal union of the 
other muscles in front ; its lateral diameter occupies about one-half 
of the space between the tuberosities of the ischia, and it is in the 
middle of this space. This muscle, besides the fixed points men- 
tioned, has at its anterior and posterior ends, many fibres ending 
simply in the subcutaneous cellular substance, and which are much 
more superficial than the fixed points. 

Besides closing the orifice of the rectum it will draw the bulb 
of the urethra backwards, or the point of the os coccygis for- 
wards. 

The Musculus Coccygeus, 

Belongs to the interior of the pelvis. It arises by a small, ten- 
dinous and fleshy beginning, from the spine of the ischium, and 
lying on the anterior face of the anterior sacro-sciatic ligament, it is 
inserted into the side of the last bone of the sacrum, and of all those 
of the os coccygis. 

It draws the os coccygis forwards. 

It frequently happens that there is on each side a small fasciculus 
of muscle arising from the inferior bone of the sacrum in front, and 
inserted into the bones of the coccyx ; it is called Sacro-Coccygeus. 

A large quantity of adipose and cellular matter exists on the side 
of the rectum, between it and the parietes of the pelvis, concealing 
the perineal surface of the levatores ani muscles. 



The Musculus Levator Ani, 

Arises, fleshy, from the back of the pubes near its symphysis, and 
from near the superior margin of the foramen thyroideum above the 
obturator internus muscle. It also arises from the aponeurosis pelvica, 
where this membrane is extended as a thickened semi-lunar chord 
from the superior margin of the thyroid foramen towards the spinous 
process of the os ischium. This second part of the origin of the le- 

Vol. II.— 12 



126 ORGANS OF GENERATION. 

vator ani is defectively described in most books on anatomy. It is 
then seen to cross obliquely, as far as the spine of the ischium, that 
portion of the obturator internus which arises from the plane of the 
ischium. 

From this extensive origin the fibres converge and descend back- 
wards, and have three distinct places of insertion; the posterior 
fibres are inserted into the last two bones of the os coccygis ; the 
middle, and by far the greater number, are inserted into the semi- 
circumference of the rectum between its longitudinal fibres and the 
circular fibres of the sphincter ani ; and, finally, the most anterior 
fibres pass obliquely downwards and backwards on the side of the 
vesical end of the membranous part of the urethra, and on the side 
of the prostate gland, and are inserted into the common place of 
junction of the perineal muscles. 

The fore part of this muscle is by some of the English anatomists, 
called the Compressor Urethrse.* 

The Triangular Ligament of the Urethra, 

Is a membrane which fills up the space below the symphysis of 
the pubes, and answers there as a septum between the perineum and 
the pelvis : when closely examined, it is seen to connect itself to the 
internal edges of the rami of the pubes and ischia on the inner pos- 
terior sides of the crura penis as far down as the beginning of the 
latter. At its lower edge its ligamentous character is not so well 
defined. On its anterior surface is the bulb of the urethra, and just 
at the extremity of the latter, enclosed by the ligament, and adhering 
to it, are Couper's Glands. In contact with it behind, and ad- 
hering, is the prostate gland, covered by its fibrous capsule, which 
is a continuation of the pelvic aponeurosis over it. A perforation 
exists in it, through which passes the membranous part of the ure- 
thra. This opening is not very apparent, in consequence of its 
edges being continued a little distance on the canal ; but by de- 
taching them the whole becomes well defined. 

The relative situation of the bulb and of the membranous part of 
the urethra is such, that the former goes towards the anus, while the 
latter passes upwards towards the neck of the bladder ; they conse- 
quently, form a considerable angle with each other. The raem- 

* Wilson's Anatomy, p. 198. 



MUSCLES AND FASCIA OF THE PERINEUM. 127 

branous part of the urethra is much the deepest, the recollection of 
which, is all-important in lithotomy, as it teaches us to avoid the 
one, and to cut into the other. It may also be observed, that the 
hole in the triangular ligament is an inch below the symphysis pubis. 
By removing the upper corner of the triangular ligament, we are 
made acquainted with another just behind it, which is totally distinct. 
This ligament is half an inch broad, is thick and strong, particularly 
at its lower edge, and is very firmly attached laterally to each of the 
ossa pubis, just below the symphysis : it is a continuation of the liga- 
mentous union of the symphysis pubis. Mr. Colles calls it pubic 
ligament with great propriety. I would suggest, as somewhat more 
expressive, the term Inter-Pubic Ligament •* as it serves to distin- 
guish it from another called Pubic, which is above the pubes, and 
described in the account of the recti abdominis muscles. The 
breadtli of this having been stated at half an inch, it is obvious that 
the hole in the triangular ligament is half an inch below its lower 
edge. 

Pelvic Fascia. 

The Pelvic Fascia [Aponeurosis Pelvica) connects the bladder to 
the sides of the pelvis. " This fascia descends from the ileo-pecti- 
neal line to about midway in the depth of the pelvis ; here it is re- 
flected from the surface of the muscle, (the Levator Am,) and applies 
itself to the prostate gland and bladder on the body of which it is 
ultimately lost. At the angle of its reflection, this fascia appears par- 
ticularly strong and white, but becomes more weak and thin as it 
lines the muscle and covers the bladder. In tracing this membrane 
it will be seen that from the pubes just below the symphysis, a point- 
ed production of it, constituting its anterior margin, is fixed into 
the side of the neck of the bladder. This pointed production on 
each side is called, by most anatomists, the anterior ligaments of the 
bladder. Between them, just beneath the symphysis of the pubes, 
a pouch large enough to receive the end of the finger, is formed by 
the union of the fasciae of the two sides : this pouch connects the 
middle anterior part of the neck of the bladder to the lower margin 
of the symphysis pubis. "f 

This fascia adheres closely to the periosteum of the pubes, between 
the upper margin of the thyroid foramen and the crista of the pubes ; 

* See Symphysis Pubis. f Colles' Surgical Anatomy. 



128 FEMALE ORGANS OF GENERATION. 

about the middle third of the linea innominata it is obviously a con- 
tinuous membrane with the iliac fascia which covers the iliacus in- 
terims muscle ; but behind this, again, it arises from the remaining 
third of the linea innominata. 

The portion of this fascia which Mr. Colles speaks of as parti- 
cularly strong and white, forms a bow, the concavity of which looks 
upwards, one end of the bow being fastened to the pubes above the 
foramen thyroideum, and the other end to the ischium above its 
spine. The perineal surface of this bow is an important point of the 
origin of the levator ani. Above the bow this fascia is very thin, for 
the fibres of the obturator internus can be readily seen through it. 

At the bow the fascia divides into two lamina? ; one pursuing its 
course to the bladder and rectum, the other covers the lower part 
of the obturator internus muscle, and thereby constitutes the obtu- 
rator fascia. The levator ani is interposed between these two laminae. 
The aponeurosis pelvica also forms a bow or semi-lunar edge in front 
of the sacral nerves. The triangular ligament and this fascia are so 
identified in forming the capsule of the prostate, that the capsule in 
description, may be referred either to the one or the other, or to both, 
according to the fancy of the describer. 



CHAPTER II. 

Of the Organs of Generation in the Female.* 

The Copulative Organs in the female are, the Vulva and the 
Vagina; the Generative are the Uterus and the Ovaria. 

SECT. I. — OF THE VULVA. 

The term Vulva is applied to the most superficial of the copulative 
organs, and consist in the Mons Veneris, the Labia Externa, the 
Labia Interna, the Clitoris, the Vestibulum, the Orificium Urethra?, 
the Fourchette, and the Fossa Naviculars. 

* Anat. Atlas, Fig. 39G to 403, inclusive.. 



THE VULVA. 129 

The Mons Veneris is the protuberance on the fore part of the 
pubes. Its size varies considerably, according to the state of obesity 
of the subject, in consequence of its being formed by a deposite of 
fat between the skin and the bone : in corpulent women it is very 
large and prominent, whereas, in such as are much emaciated, it 
simply describes the outline of the bones. The skin, there, is abun- 
dantly furnished with its peculiar glands, seated in the cellular texture 
beneath it, and about the size and shape of millet seed. At the age 
of puberty a growth of hair takes place upon it, which is not so long 
as the correspondent growth upon men, and is not so much disposed 
to spread itself over the lower part of the abdomen as life advances. 
In women who have abused coition, it is said that these hairs become 
much curled. 

The Labia Externa are a continuation of the mons veneris down- 
wards in the form of an oblong eminence on either side. Their 
elevation is produced in the same way by a deposite of fat beneath 
the skin. They are somewhat broader and more prominent above 
than below. On the side which is next to the thigh, the integu- 
ment is common skin, sparingly covered with hair; but on the other 
face it is a mucous membrane, being a continuation of that of the 
vagina. The skin here, as well as at the commencement of every 
mucous membrane, is insensibly changed into the latter. They 
have many sebaceous and perspiratory glands externally, and mu- 
cous glands internally, upon them. 

Much cellular membrane, like that of the scrotum, is found in 
their interior structure; whereby they enjoy great extensibility in 
order to favour the dilatation of the parts in parturition. The rima 
which exists between them is the Fissura Vulvas of authors, and is 
about twice the length of the orifice of the vagina; this arrangement 
of it gives increased facility to the expulsion of the fetus. 

The Fourchette or Frenulum Vulvas, is situated at the posterior 
commissure of the labia externa, and is a thin, narrow transverse 
duplicative of skin ; which, owing to its weakness, is most fre- 
quently ruptured at the first act of parturition, and then disappears. 

The Clitoris bears, in some respects, a resemblance to the penis 
of the male, but is by no means so large. It is situated immediately 
below the symphysis pubis, and consists in a cylindrical body of 
three or four lines in diameter, with two crura. The body is an. 

12* 



130 FEMALE ORGANS OF GENERATION. 

inch long; the crura are likewise of the same length, and arising 
from the internal face of the crura of the pubes, unite beneath the 
symphysis so as to form the body. The body is not straight, but 
has the anterior half bent downwards and forwards. The exterior 
covering, or capsule of the clitoris, in its texture, resembles the 
elastic ligamentous membrane of the corpus cavernosum penis; and 
is, moreover, filled within by a similar cavernous or cellular struc- 
ture, which is divided into two equal parts by a septum pectiniforme, 
and is susceptible of distention during sexual excitement. The 
clitoris is supplied also with blood vessels and nerves like the penis, 
and is held up to the under part of the symphysis pubis by a sus- 
pensory ligament. 

The anterior extremity of the body of the clitoris is found in the 
rima or fissura vulvas, about an inch below the upper commissure 
of the labia externa. It projects somewhat, and bears a general 
resemblance in shape with the end of the penis, whence its name 
of glans clitoridis; but it has not the same organization, excepting 
the delicacy, the extreme sensibility, and the vascularity of the skin 
which covers it. The clitoris has no corpus spongiosum, neither is 
it concerned, like the penis, in conveying the urine from the blad- 
der. Its glans is covered by a doubling of skin called the prepuce, 
and is likewise furnished with the glandular Tysoni, from which is 
discharged a smegna, or sebaceous fluid, as in the male. The pre- 
puce does not furnish a regular well defined frsenum. 

The Erector Clitoridis muscle corresponds with the erector penis. 
It arises from the ascending ramus of the ischium, and, covering 
the inferior face of the cms clitoridis, runs as far forwards as the 
commencement of the body. 

The Labia Interna, or Nymphse, are two duplicatures of the 
mucous membrane of the vulva, which pass down, one on each 
side, from the clitoris. The prepuce of the latter terminates, on 
either side, in the labia; while the latter are continued upwards, 
by a narrow process, to the under surface of the glans clitoridis. 
They arise all along their base, from the internal sides of the labia 
externa, or raajora; and being wider in the middle than elsewhere, 
they terminate insensibly about half-way down the orifice of the 
vagina. Between the laminae of each one is placed a vascular 
cellular substance, susceptible of distention and of partial erection 
during sexual excitement. In young subjects, their vascularity 



THE VULVA. 131 

communicates a vermilion tinge, which is lost and becomes brown- 
ish in the progress of life. As they are effaced during parturition, 
their chief use seems to be as a provision for the great distention of 
the vulva* which then occurs. 

The labia interna are about half an inch broad in the natural state, 
and do not project obviously beyond the labia externa, except in 
cases of extreme emaciation, where the prominence of the latter has 
been destroyed by a removal of its fat. They are, however, very 
subject, as the individual becomes old, to a pointed elongation, in- 
creasing their breadth to an inch, or an inch and a-half ; and to be- 
come thickened and indurated. A tribe of Hottentots, the Boschis- 
mans, living near the Cape of Good Hope, are uniformly subject to 
this enlargement; which, for a long time, was represented, by 
travellers, as an organ superadded to what is common in the human 
species. 

The Vestibulum is a depression of twelve or fifteen lines long 
between the labia interna ; it is bounded above by the clitoris, and 
below by the orifice of the vagina.. It is abundantly furnished with 
mucous lacunae. 

The Urethra of the female has its external orifice (Orificium 
Uretltrce) in the inferior part of the vestibulum, about one inch 
below the glans clitoridis, and is generally marked by a slight 
rising, which is easily distinguished by the sensation of touch 
alone ; its margin is often bounded by a little caruncle on each 
side.* The urethra itself is an inch long, larger and much more 
dilatable than that of the male, its course is obliquely downwards 
and forwards from the neck of the bladder; passing under the 
symphysis of the pubes, and being slightly curved from that cause. 
It consists of two membranes, a lining and an external one. The 
lining membrane is a continuation of that of the bladder; it is 
thrown into several longitudinal folds, and has many mucous folli- 
cles in it. The external coat of the urethra consists of condensed 
laminated cellular membrane, having a strong affinity with mus- 
cular fibre: the principal direction of the fibres is transverse, form- 

* Professor Pancoast considers the urethra of the young female to have its 
orifice on a level with the anterior face of the Symph. Puhis, whereas, in such as 
have borne many children it is behind the pubes. Wistar's Anat. vol. ii. p. 
182. Phil. l^y. 



132 FEMALE ORGANS OF GENERATION. 

ing a cylindrical body of half an inch in its transverse diameter, 
and which has given the idea of the existence of a prostate gland 
in the female : the lower and lateral surfaces of this cylinder are 
in contact with the vagina, forming a protuberance into its cavity; 
and the upper surface is firmly connected to the triangular liga- 
ment of the pubes. Immediately behind the neck of the bladder, 
we find the vesical triangle with its muscle, as in the male, except- 
ing that the anterior angle of it goes to the anterior end of the 
urethra. 

The Fossa Naviculars is that portion of the rima vulvse which 
is below the vestibulum, and anterior to the orifice of the vagina. 



SECT. II. — OF THE VAGINA. 

The vagina is a thin membranous canal which leads from the 
vulva to the uterus. It is from four to six inches in length, differ- 
ing according to age and pregnancy, and being much shorter in 
women who have borne children than in virgins. It is placed be- 
tween the bladder in front, and the rectum behind, being flattened 
by them so as to bring its anterior and posterior surfaces into con- 
tact. Its anterior extremity is the smallest of the two ; and pre- 
sents its greatest diameter vertically, while that of the posterior is 
transverse. As it follows accurately the central line of the pelvis, 
it is, consequently, curved with its concavity forwards. Its ante- 
rior parietes are shorter than the posterior, both from the smaller 
depth of the pelvis in this direction, and from the mode of con- 
nexion with the uterus. 

The vagina is formed by two tunics ; a fibrous and a mucous 
one. The first is external, of a light red colour, highly elastic, 
and seems to consist of condensed cellular membrane, the fibres 
of which are much intermixed, and pass in every direction. It is 
vascular, and immediately adjacent to the large venous sinuses of 
the pelvis. The mucous membrane being a continuation of that 
of the vulva, is at and near its anterior orifice of a vermillion tinge; 
while, posteriorly, it is grayish and frequently spotted, so as to give 
it a marbled appearance: its thickness diminishes as it recedes 
from the external orifice; and upon being floated in water, many 
mucous lucunae are observable upon it. 

The internal surface of the vagina is commonly covered with 



THE VAGINA. 133 

the mucus which comes from its lacunae. On the anterior or 
pubic portion, it is divided longitudinally by a middle ridge, which 
commences by a sort of tubercle just below the orifice of the 
urethra, and proceeds backwards, becoming indistinct as it ap- 
proaches the uterus. Transverse ridges formed in the same way 
by folds of the mucous membrane, arise from the sides of the last 
at its anterior portion, and give a roughness to that part of the va- 
gina. The inferior side, or that next to the rectum, has the same 
kind of arrangement of the mucous membrane, but not os distinct. 
In a majority of subjects, the uterine half of the vagina is perfectly 
smooth, but the rule does not always hold. The internal membrane 
of the vagina is covered by its epithelium, the scales or cells of 
which are detached and found in the secretion of mucus. 

The Corpus Spongiosum Vaginae is an erectile tissue, like that of 
the penis, and closely resembles in structure the corpus spongiosum 
urethrae. It is placed at the anterior end of the vagina, on its outer 
circumference, just below the clitoris, and at the base of the labia 
minora or interna. It is an inch broad, and a line or two thick, ad- 
heres closely to the fibrous coat of the vagina, and extends around 
the superior semicircumference of the orifice, but not around the in- 
ferior. It is frequently called Plexus Retiformis. 

The Sphincter Vaginae Muscle surrounds the anterior orifice of 
the vagina, and covers the plexus retiformis. It is about an inch 
and a quarter wide, and arising from the body of the clitoris and 
the cms of the pubes, behind the crus of the clitoris, passes back- 
wards and downwards to be inserted into the dense, white sub- 
stance, in the centre of the perineum, common to these muscles, 
the transversi perinei and the anterior point of the sphincter ani. 
There is a strong analogy between, it and the accelerator urinae of 
the male. 

The Transversus Perinei of the female, has the same circum- 
stances of origin and insertion as in the male, but is not quite so 

strong. 

On each side of the orifice of the vagina, near its middle, is fre- 
quently found a mucous gland, the size of a garden pea : it corre- 
sponds with Couper's gland of the male subject. 



134 FEMALE ORGANS OF GENERATION. 

The Hymen,* one of the attributes of the virgin state, is placed 
at the anterior orifice of the vagina for the purpose of closing it, and 
commonly remains until it is ruptured by violence. In all cases 
except where there is an unnatural adhesion, it leaves a small orifice 
for the passage of mucus and of menstrual blood. In my own ob- 
servations, I have found it most frequently crescentic, the convexity 
of the crescent presenting downwards, and the horns upwards ; but 
in some cases it is to one side. Next in frequency to the lunated is 
the circular shape, where it surrounds completely the orifice and 
leaves a hole in its own centre. There are some other varieties, 
such as its being fleshy, fasciculated, unequally divided into two 
portions, and so on, which are narrated by different writers. Being 
simply a duplicature of the mucous membrane, it is generally so weak 
as to be ruptured at the first act of copulation ; or even from slighter 
causes during infancy : but occasionally, it becomes thickened, and 
so strong as to require division with the knife. Upon the rupture of 
the hymen, its place is indicated in subsequent life by from two to 
six small tubercles, called Carunculae Myrtiformes, which are its 
remains. 

The peritoneum, in descending from the uterus, anteriorly, 
touches the top of the vagina for a little distance, and is then re- 
flected to the bladder, but posteriorly, almost the upper half of the 
vagina has a peritoneal coat before this membrane is reflected to the 
rectum. The attachment of the vagina to the bladder is strong and 
close just above the urethra, but its connexion with the rectum is by 
rather loose cellular substance. 



SECT. III. — OF THE UTERUS, AND ITS APPENDAGES. 

The Uterus, or Womb, is a compressed pyriform body, the larger 
end of which stands upwards, while the lower is directed down- 
wards, and is attached to the vagina. f Unimpregnated, it is two 

* J. G. Tolber, Diss, de Variet. Hymen.— Haller, Icon. Anat. Fasc. i.— 
Albin. Acad. Annot. Lib. iv. — Santorini, Septemd. Tab. 

f This is commonly represented by anatomists in their plates and descrip- 
tions as the position of the womb ; it is, however more so in advanced preg- 
nancy than when empty. In my dissections generally, I have found the pos- 
terior face of the womb downwards, reposing upon the concavity of the rectum, 
and the os tincae obliquely forwards; this position being probably produced by 



UTERUS, AND ITS APPENDAGES. 135 

and a half inches long, and one and a half in diameter at its widest 
part. The posterior face is very convex, while the anterior is al- 
most Hat, or very slightly convex. It is about one inch in thick- 
ness. It is divided by anatomists into fundus, body, and neck. 
The fundus is formed by its superior extremity, and comprises the 
space between the orifices of the Fallopian tubes : the neck is the 
lower cylindrical portion, of about an inch in length ; and the body 
is the part intermediate to the two. On the exterior circumference 
of the uterus, there are no marks or lines distinguishing these several 
portions, from each other. 

The uterus, being destined to lodge the foetus from a short pe- 
riod after conception to the moment of birth, has a cavity ready 
for its reception. The shape of this cavity bears some general, but 
not a rigid resemblance to that of the organ itself, and it is so 
much flattened as to have its anterior and posterior parietes in con- 
tact, or nearly so. The cavity of the body is an equilateral trian- 
gle of eight or ten lines in diameter; the sides of the triangle are 
bent inwards in parabolic curves, in such a way as to present their 
convexities to the cavity of the uterus: this of course, occasions an 
apparent elongation of the angles. The inferior angle is continued 
into the cavity of the neck, while the two superior run into their 
respective Fallopian tubes. From this arrangement it happens that 
the parietes of the uterus are only three lines thick on the angles 
of the triangular cavity, while at the middle they are from four to 
six lines. The cavity of the neck has not its anterior and poste- 
rior sides so near together as those of the body; and is rather cy- 
lindrical, being smaller, however, at the upper and lower ends than 
in the middle. This arrangement gives to its sides a paraboloid 
curvature which presents its convexity outwards, differing in that 
respect from the corresponding curvature in the cavity of the body. 

The cavity of the neck terminates in the vagina by an orifice 



the superincumbence of the small intestines, and, especially, when the blad- 
der is empty. When the latter is full, the peritoneum is reflected from the 
centre of the uterus to the posterior face of the bladder, and its traction has the 
effect of erecting the uterus in part, from its nearly horizontal direction. In the 
dissection of a female, April 9, 1838, aged eighteen, who died from an affec- 
tion of the brain, there being every evidence of soundness in the genital organs, 
I lound the rectum making a curve to the right side of the inferior part 
of the sacrum, and the body of the womb, reposing in the concavity of the 
latter. 



136 FEMALE ORGANS OF GENERATION. 

about the size of a small Writing-quill, but ovoidal, and presenting 
its long diameter transversely. This Orifice is the Os Tincse, or 
Orificium Externum Uteri ; frequently, without apparent disease, I 
have seen it conoidal, with its base, half an inch in diameter, pre- 
senting downwards. The upper orifice whereby the cavity of the 
neck communicates with that of the body is not subject to such 
fluctuations in size: it is occasionally called Orificium Internum 
Uteri, and is generally somewhat larger than a small writing-quill. 
The os tincae is bounded before and behind by the lips of the uterus, 
formed by the projection of the neck into the vagina. For the 
most part the anterior lip is directly continuous with the anterior 
side of the vagina: so that its projection is very inconsiderable, 
and, indeed, not appreciable to the finger : at the same time, this lip 
is rather thicker than the posterior. The projection of the latter, 
on the contrary, is always well marked, because the vagina, instead 
of being inserted into its ridge, is joined to the posterior surface of 
its base. 

The cavity of the uterus is lined by a very thin mucous mem- 
brane, a continuation of that of the vagina. This membrane is of 
a light pink colour, which changes to a Vermillion during the pe* 
riod of menstruation; it is said to be furnished with villosities, 
which, though seen with difficulty in the usual way, may be ren- 
dered apparent, by floating the uterus in water; and it adheres so 
closely to the substance of the uterus, that it forms an inseparable 
portion of it, which can neither be dissected nor macerated off en- 
tirely, as in the case of other mucous membranes. 

This membrane is smoothly laid upon the cavity of the body, and 
gives it a polished shining surface. On the cavity of the neck, it 
is wrinkled along the anterior and the posterior parts; there being 
a longitudinal line running along the centre, and on each side of 
this line transverse or oblique elevations or duplicatures. This ar- 
rangement presents an arborescent appearance, technically called 
the arbor vitse. In the interstices of these duplicatures there are 
some small mucous glands or lacunae, which as their orifices are 
exposed to obliteration from inflammation or some other irritation, 
become distended into small spherical sacs by the accumulation of 
their habitual secretion. Naboth, from seeing them in this state, 
mistook them for eggs, or the rudiments of the foetus, and the 
error has been commemorated by their being called Ovula Na- 



THE VAGINA. 137 

bothi. This membrane is covered by an epithelium which is vibra- 
tile to the middle of the neck, and afterwards pavement-like. 

The uterus is covered completely by the peritoneum ; in the re. 
flection of the latter, from the rectum to the bladder, it adheres to 
the uterus by a subjacent cellular substance, which allows it to be 
dissected off without difficulty. The same duplicative of peritoneum 
which encloses the uterus, is also reflected from each of its lateral 
margins, by their whole length to the corresponding side of the lesser 
pelvis, and forms the Lateral or the Broad Ligaments, (Ligamenta 
Lateralia, Lata.) The peritoneum in passing from the uterus for- 
wards to the bladder, forms on each side, a duplicature, not very 
distinct, and depending, in a measure, upon the state of the bladder; 
this constitutes the Anterior Ligament. The same membrane in 
passing from the back of the uterus to the rectum, and in covering 
the posterior superior end of the vagina, also forms, on each side, 
a duplicature, denominated the Posterior Ligament; it is always 
better seen than the anterior. Muscular fibres are said to be found, 
occasionally, between the lamina? of these several duplicatures, run- 
ning in the direction of the latter;* they have not been presented to 
me in such a way as to arrest my attention. 

The broad ligaments, along with the uterus, form a transverse 
septum, passing from one side of the pelvis to the other ; and con- 
tain, between their laminae, the arteries and the veins which belong 
to the uterus and ovaries. 

Besides the duplicatures of peritoneum, the uterus is retained in 
its position by the Ligamenta Rotunda, one on each side. These 
round ligaments arise from the side of the uterus, a little below the 
insertion of the Fallopian Tube, and going between the laminae of 
the broad ligament, reach, finally, the internal abdominal ring : they 
then traverse the abdominal canal and the external ring after the 
manner precisely of the spermatic chord, and terminate by several 
fasciculi in the fatty cellular matter of the mons veneris and of the 
labia majora. The round ligaments are rather smaller in the middle 
than at either extremity ; they consist of a condensed cellular or 
fibrous structure, and have many blood vessels in them. It has 
been asserted,! that they contain strongly marked muscular fibres ; 
some of which come from the uterus, and others from the broad 

* J. F. Meckel, vol. ii. p. 605. f J, F. Meckel, loc. cit. 

Vol. II.— 13 



138 FEMALE ORGANS OF GENERATION". 

muscles of the abdomen. No evidence of this fact has as yet been 
presented to me, though I do not deny it; and, indeed, I think it 
probable, that such fibres may be developed there during gestation. 

The texture of the uterus is very compact, and of a cartilaginous 
feel ; it is composed of fibrous matter, intermixed with a great many 
blood vessels. In regard to its fibrous structure, there is no subject 
in anatomy upon which opinions are more divided, or more authori- 
tative and numerous on both sides of the question. Some deny its 
existence at any period, while others admit it as a constant condi- 
tion : others, again, limit its duration only to the period of pregnancy. 
Without dwelling on the value of the several doctrines, and the 
means and observations tending to support them, it may be suffi- 
cient here to mention that the structure of the uterus takes on very 
important and strongly marked changes, in passing from the unim- 
pregnated state to that of advanced gestation. In the first the fibres 
look ligamentous and pass in every direction, but so as to permit 
the uterus to be lacerated more readily from the circumference to 
the centre than in any other course : it, indeed manifests an indis- 
position to be torn in a laminated manner. The fibres, mot cover, 
break off short, are separated by the blood vessels, and seem to con- 
tain, in their interstices, something like fibrine. 

In the impregnated state, on the contrary, the vessels being im- 
mensely increased in size, the laminated structure becomes very 
evident, and submits readily to the tearing of one layer from the 
other : these laminae consist of fibres, which are principally parallel 
with each other. The muscular nature of these fibres seems to be 
sufficiently proved, by their powerful contraction in the expulsion of 
the foetus, and on being irritated by the introduction of the hand. 
They are, however, not red like other muscles, but of a very light 
colour as those of the bladder and intestines; and are collected into 
fasciculi of peculiar flatness and looseness. The development of 
this muscular structure is not, always, limited to the pregnant state, 
but is disposed to manifest itself on many occasions which produce 
an increased size in the uterus. This fact was first exemplified to 
me in a small scirrhus of a virgin uterus, presented by Dr. Hugh 
L. Hodge,* and has been still farther confirmed in a case, where 
the scirrhus was five or six inches in diameter ; also in a virgin 
uterus, very much enlarged from scirrhus, presented by Professor 

* Now Professor of Obstetrics in the University of Pennsylvania. 



UTERUS, AND ITS APPENDAGES. 139 

Charles D. Meigs.* A similar fact has been noticed by Lobstein, 
of Strasburg, where the tumour was also steatomatous. 

The fibres of the uterus, examined near the term of pregnancy, 
consist in two planes separated by the large bloodvessels; one 
within and the other without. These layers are readily divisible 
into subordinate laminae, intermixed with one another but yet to a 
considerable extent separable. The external layer is thicker than 
the internal, and both have an increased thickness at the fundus : 
while they are much diminished, and indeed indistinct, at the 
cervix. 

The fibres generally are either circular or longitudinal, but many 
of them are oblique. The exterior surface of the external plane, is 
composed principally of longitudinal fibres, within which are the 
circular. The inner plane, on the contrary, has the circular fibres 
external, and the longitudinal internal. In both planes the circular 
fibres are more abundant at the fundus, and the longitudinal upon 
the body of the uterus ; but, generally speaking, there are collec- 
vcly more longitudinal than circular fibres. 



Of the Fallopian Tubes. 

The Fallopian tubes (Tubes Fallopiance) are two membranous 
canals, one on either side, fixed in the superior margin of the broad 
ligament of the uterus. They serve to conduct the rudiments of 
the embryo from the ovarium into the uterus. They are about four 
inches long, and extend from the upper angle of the uterine cavity 
to the side of the pelvis: their outer extremity is loose, and hangs 
upon the posterior face of the broad ligament over the ovarium, 
consequently inclines downwards, thereby forming an angle with 
the other portion. 

At their uterine extremities the Fallopian tubes are about the size 
of the vas deferens, resemble it strongly, and scarcely admit a hog's 
bristle; but having proceeded about one-half of their length, they 
begin to enlarge, and continue to do so rapidly for an inch, until 
they reach the size of a writing-quill ; they then contract again 
somewhat, and immediately afterwards expand into a broad trumpet- 

* Of the Jefferson Med. College. 



140 FEMALE ORGANS OF GENERATION. 

shaped mouth. The latter has an oblique orifice, the edge of which 
is extremely irregular, by being resolved into a number of ragged 
fringe-like processes, of unequal size and length; and which, as a 
whole, are called Corpus Fimbriatum, or Morsus Diaboli. One of 
the longest of these processes adheres to the external end of the 
ovarium. 

The Fallopian tube is covered by the peritoneum, and consists 
of two coats : the external is fibrous, and bears sufficient resemblance 
to the structure of the uterus to be considered a continuation of it; 
the internal is mucous, and is likewise a continuation of the corres- 
ponding one of the uterus. The external end of the tube, which is 
called Pavilion by the French anatomists, is flaccid, thin, and gene- 
rally in a collapsed state, as it is formed solely by the mucous mem- 
brane, assisted by the peritoneum, neither of which furnishes re- 
sistance sufficient to keep it expanded ; but, as many blood vessels 
enter into its composition, their turgescence, in sexual excitement, 
probably communicates a certain degree of erection. 

Mr. Grainger has ascertained that the Fallopian tube presents a 
difference in the structure of its mucous membrane, the part next 
the uterus, not being so vascular as the other part: moreover, the 
latter presents a complex arrangement in the form of folds or valves 
running in a longitudinal direction and plaited. We are left to 
infer that the difference is more conspicuous shortly after concep- 
tion.* There is some similitude in this arrangement with the ovi- 
ducts of birds, one part of which secretes the albumen of the egg, 
and another part, the shell; and it may be in the human subject, also, 
that the two parts execute different offices in the perfection of the 
ovum. 

Of the Ovaries. 

The Ovaries, (Ovaria, Testes Muliebres,) two in number, one on 
either side, are situated on the posterior face of the broad ligaments 
by a duplicature of which they are surrounded, and are twelve or 
fifteen lines below the Fallopian tubes. Their shape is that of a 
compressed ovoid, about half the size of the male testicle: their long 
diameter is horizontal; they are suspended from the broad ligament 
rather by the edge than by the flat surface, so that they project, and 

* Miiller's Physiol., p. 15G3. 



THE OVARIES. 141 

are to a considerable degree pendulous. Their distance from the 
uterus varies from an inch to an inch and a-half, and from the in- 
ternal end of each one there proceeds a small vascular fibrous cord, 
the Ligament of the Ovarium, which is inserted into the uterus, 
somewhat below the origin of the Fallopian tube. 

From their being the seat of conception, they have, in the youth- 
ful and healthy female, a pliancy and succulency, indicative of their 
state of preparation for the act; but in advanced life they diminish 
much in volume and become hard and dry. Their surface, origi- 
nally smooth or slightly embossed, is subsequently rendered uneven, 
by repeated acts of conception, leaving on it a number of cicatrices 
or small stellated fissures. They are of a light pink colour. 

Within the peritoneal coat is another, the Tunica Albuginea, of 
a strong, compact, fibrous texture, like the same coat of the testicle, 
and sending inwards many processes. 

The structure of the ovarium is as follows: But few females, of 
those presented in our dissecting rooms, have the part in a state fit 
for study, owing to age, disease, or excessive sexual indulgence : 
my best opportunities have been derived from post mortem exami- 
nations, in private, of individuals of from fourteen to twenty, where 
the virgin state had been preserved. When an ovarium of the 
latter kind can be got, by cutting through the tunica albuginea 
simply, and then tearing open the organ, it will be found to consist 
of a spongy fibrous tissue, abundantly furnished with blood vessels 
from the spermatic artery and vein. In this spongy tissue, called 
Stroma,* are from fifteen to twenty spherical bodies, the Graafian 
vesicles, (Ovula Graqfiana,) according to the commonly received 
opinion; but in an ovarium exhibited to me by the late Dr. John. 
Hopkinson, there were thirty-six distinct vesicles. They vary in 
size from half a line to three lines in diameter ; the larger ones are 
nearer the surface, and from having caused the absorption of the 
tunica albuginea, may sometimes be seen through the peritoneal 
coat, and give to the surface of the ovarium an embossed condition. 
The vesicles contain a transparent fluid having within it the rudi- 
ments of the embryo. As the vesicles are evolved they advance 
from the centre to the circumference. Their parietes are thin, trans- 
parent, and have creeping through them minute arterial and venous 



* By von Baer, from its being a bed (stratum. ) 

13* 



142 FEMALE ORGANS OF GENERATION. 

ramifications. The bed of the ovarium in which a vesicle reposes 
is called the calyx. 

To Von Baer* belongs the merit of discerning first the ovulum 
of man and of mammalia in the Graafian vesicle. The Ovulum occu- 
pies but a very small part of the cavity of the Graafian vesicle, the 
remainder being filled with an albuminous fluid in which micro- 
scopic granules float. By discharging the fluid from a Graafian 
vesicle, the Ovulum can with a simple lens be detected in a globu- 
lar form and floating in this fluid. By flattening out this little globe 
under a thin plate of glass, and then examining with a compound 
microscope, it will be seen that it consists of a transparent membrane 
containing a Vitellus or yolk made of granules or cells and fat glo- 
bules. 

Within the above vitelline membrane is placed the Germinal vesi- 
cle of the human subject,! being about ^ of a line in diameter. 
This vesicle has also the germinative spot, macula germinativa of 
Wagner, which is from the uuc to sh of a line in diameter. 

The Ovula Graafiana seldom project much on the surface of the 
ovarium in the human subject; but in other animals, as the common 
hen, they, upon being developed, stand out so much as to resemble 
a cluster of berries each attached by its pedicle, and surrounded by 
its two appropriate sacs. These sacs constitute what are called the 
capsule of the ovum or the ovisac. Upon the inner surface of this 
capsule, according to the observation of Schwann, is to be found a 
layer of epithelial cells in the different classes of animals, as for ex- 
ample, in the ovicapsules of fish, and in the Graafian vesicles or 
ovules of mammalia. The existence of these epithelial cells is con- 
sidered as proof positive of the sameness of the membrane in what- 
ever animals it may be examined ; and, therefore that the ovicapsules 
of oviparous animals are identical with the Graafian vesicles or ovula 
of mammalia. The stages of development in an egg are, therefore, 
simply the expression of what occurs also in a Graafian vesicle. 

Within the ovicapsule of Birds is the yolk (vitellus) surrounded 
by its membrane called vitelline, which being at first in contact with 
the capsule, is afterwards separated from it in many animals by a well 
marked and large interval. The yolk is formed of fine cells con- 
taining granules and oil globules. 

*• Miiller. p. 14GP. 

| Discovered by Coste in 1834, and more distinctly explored by Valentine 
33d Bernhardt. Miiller, p. 1471. 



THE OVARIES. 143 

In the substance of the yolk is the vesicle of Purkinje, or the Ger- 
minal vesicle. This vesicle contains a transparent fluid, and has 
on it a nucleus, called the macula germinativa. This vesicle in the 
fully formed ova of the oviparous vertebrata is imbedded in a disk- 
shaped layer of granular substance, called the germ disk. The ger- 
minal vesicle is finally lost by commingling with the granular matter 
of the germ disk, in which the first rudiments of the embryo are 
formed. 

Upon the ovum leaving the ovarium in a bird it has to pass through 
the oviduct, and in doing so receives as a deposite upon it the white 
or albumen, and subsequently the shell which is also due to the se- 
cretory action of the oviduct.* 

The analogy is thus seen to be striking between the evolution of a 
common egg and the ovule of the human subject, found in the 
Graafian vesicle. 

A very remarkable point, mentioned by Carus, is that all the 
essential parts of the ovulum can be detected in the ovary of the 
mature embryo of the human subject or of mammiferous animals, 
hence the preparation for a new generation seems to begin at a very 
early period of life. 

When an ovulum is discharged from a Graafian vesicle the latter 
and the surrounding calyx open in a stellated line: this line of de- 
hiscence or gaping is in birds preceded by a whitish arched band 
called the stigma, which indicates the place for the escape of the 
ovum. There appears to be some analogy in this with the spon- 
taneous fissure of the rind or bur of certain fruits. 

Upon the escape of the contents of the Graafian vesicle the latter 
is first filled with coagulating lymph or blood, or rather undergoes a 
pullulation from its interior surface, so as to form a body called the 
Corpus Luteum, which being after a while absorbed the vesicle 
collapses and shrivels, and the stigma then remains permanently as 
a stellated cicatrix. Sometimes the entire surface of the ovarium is 
marked with those stigmata. 

The phenomena attending the formation of the corpus luteum 
have elicited great interest, of late years, and many very scientific 

* A satisfactory explanation of the above process, according to Wagner and 
others, is found in Muller's Physiol., p. 1468. London, 1842. 



144 LACTIFEROUS GLANDS. 

observations have been made on the subject by BischofT,* Wagner,f 
Huschke,! and others. 

The Organs of Generation in the female are supplied with blood 
principally from the internal pudic and other branches of the hypo- 
gastric artery: the corresponding veins run into the hypogastric. 
Their nerves come from the sacral and from the hypogastric plexus. 
The arteries of the Ovarium come from the Spermatic and from the 
uterine. Former anatomists considered the spermatic to be the prin- 
cipal one — the opinion is now changing in favour of the branch of 
the uterine. The spermatic veins discharge as in the male sub- 
ject. 

The Bladder and the Rectum, with unimportant exceptions, are 
the same in both sexes. The Levator Ani, the Coccygeus, and the 
Sphincter Ani, are also similar. The pelvic aponeurosis in the 
female, besides connecting the bladder to the sides of the pelvis, 
is attached to the anterior part of the vagina. The triangular liga- 
ment of the urethra also exists, but under circumstances somewhat 
modified by the close connexion of the urethra with the vagina. 



CHAPTER III. 

Of the lactiferous Glands, or Breasts.§ 

The Breasts (Mamma) of the female are intended for the secre- 
tion of milk, and thereby to maintain the connexion between mother 
and infant for some time after the uterine life of the latter is passed. 
All mammiferous animals exercise this function : in birds there is a 
sort of substitute for it, in the changes which take place in the first 
stomach or crop during incubation. In the male subject there is, 

* Trait, de Develop, de L. Homme. Paris, 1843. 
f Elements of Human Physiol. Parti. London, 1841. 
X Traite de Splanch. Paris,. 1845. 
§. Anat. Atlas, Figs. 404 to 410, inclusive. 



LACTIFEROUS GLANDS. 145 

also, a small glandular body on each side, which has the same or- 
ganization as in the female, but is in miniature, and always remains 
in a collapsed stale, with some rare exceptions ; when it has been 
known to expand in volume, and to furnish a secretion, as in the 
female.* 

The Breasts are two in number, one on either side; they are 
situated on the same level, in front of the pectoralis major muscle, 
and between the arm-pit and the sternum. They are hemispherical, 
and have their base united to the muscle by a thin lamina of loose, 
extensible, cellular substance, containing, even in corpulent women, 
but little fat. The skin which covers the front of this gland is very 
fine and thin, so that the blood which circulates in its veins maybe 
readily seen. Between the skin and the front surface of the gland, 
there is a considerable thickness of cellular adipose matter, which, 
from its superabundance in some individuals, gives to them an ap- 
pearance of having the glands enormously enlarged. There is, 
however, a great variety in the size of the glandular structure itself; 
for, in females who are youthful and giving suck, they are much 
larger than in such as have passed the period of child-bearing, and 
whose health is impaired. When all the fatty matter has been re- 
moved from a breast, and it is permitted to repose upon a table, 
its hemispherical shape disappears, and it then seems rather a 
flattened circular disk, of from four to five inches in diameter. 

The mamma is of a very light pink colour ; and though very flac- 
cid and yielding on being handled, its texture is actually extremely 
tough, and is cut only by much force. With the exception of bone, 

* In a male patient, a resident in the Philadelphia Alms House, the pheno- 
menon of a full evolution of the glandular structure in both breasts is mani- 
fested. The individual (James Mclntyre) is forty five years of age ; the breasts 
are as large as those of a nursing woman ; but the nipples are not proportionately 
evolved. Though his frame is robust, and well set, the voice is feminine ; his 
external organs of generation are about the size of those of a boy of fourteen or 
fifteen. Thinking that there might be an internal state approaching to herma- 
phrodism, he informed me, on inquiring, that in earlier life he had the common 
inclinations for the female. He also informed me that this unusual develop- 
ment took place seven or eight years ago, owing to an excessive salivation; 
but, as he has a reserve on the subject, this statement may, probably, be re- 
ceived with some qualifications. I have also seen a second case, in which the 
voice is weak and feminine, but the genital organs have not been examined. — 
July, 1826. 



146 LACTIFEROUS GLANDS. 

it dulls a knife sooner than any other tissue of the body. Its grosser 
arrangement consists in lobes of different sizes, united in such a way 
by cellular texture, that, though they can be pulled somewhat apart, 
they cannot be entirely separated without injury. These lobes, 
when examined through the skin, give to the gland a knotted feel, 
and are sometimes partially affected by inflammation, so as to be- 
come still more distinct. The lobes are composed of Lobuli, which 
are resolvable by maceration and particular modes of treatment, into 
small graniform masses (acini) about the size of millet seed, and 
which contain the ultimate glandular arrangement. The acini them- 
selves consist of very small oblong vesicles, united by cellular 
substance, and by the common blood vessels ; and are said to be 
very apparent by the aid of a microscope in a lactescent gland.* 
These vesicles (Cellulae Lactiferse) have a diameter from ten to thirty- 
five times greater than that of the smallest capillary vessel of the 
body,f or according to Krause from the 1-27 to the 1-14 of a 
line. 

These vesicles terminate by large openings into the incipient ex- 
tremities of the lactiferous ducts, having no particular conduit as in 
the liver, the pancreas and the parotid. 

Each vesicle is surrounded by a fine close vascular net-work, 
which is displayed upon its walls, but according to the opinion of 
the day does not discharge into it. 

The Excretory Ducts (Ductus Galactophori, Lactiferi) of this gland 
are numerous. J They are of an arborescent shape, and begin by 
very fine extremities or ramuscules in the acini ; the ramuscules from 
several acini coalesce into a larger branch ; several branches unite 
to form one still larger, and so on, successively, until a lactiferous 
trunk, constituting as it were, the body of the tree, is formed by this 
assemblage. These trunks vary considerably in size, according to 
the number of tributary branches, and having got towards the centre 
of the gland near the nipple, from two to four of them, according 
to Cuboli, run into a common tube or root, called a Lactiferous 

* Marjolin, Manual D'Anat. J. F. Meckel, Manual D'Anat. 
f Miiller, loc. cit. p. 488. 

£ Alex. Kolpin, Dis. Inaug. de Struc. Mam. Cubolo, Append, ad Sep- 
temd. Tab. Santorini. Girardi, Append, ad. Septemd. Tab. Santorini. 



LACTIFEROUS GLANDS. 147 

Sinus. These Sinuses are in all about fifteen : they are only a few 
lines long, and differ in size ; some not being larger than one lacti- 
ferous duct, while others have a diameter of from two to three lines. 
The sinus at the end next to the nipple terminates in a sort of 
rounded cul-de-sac ; but from the extremity of the sac a conoidal 
tube arises which runs through the nipple, and conducts the milk : 
the point of this tube is very fine, and ends on the top of the nipple. 
This tube, from its shape, is suited to the retention of milk ; in ad- 
dition to which, it is sometimes dilated in the middle ; is curved 
when the nipple is not in a state of erection or stretched out, and 
terminates by an external orifice, which is so small as to be seen 
with difficulty by the naked eye. 

The excretory ducts of the breast, under which term maybe com- 
prehended the lactiferous ducts, the sinuses, and the conoidal tubes 
in the nipple, are formed by a soft, thin, and semi-transparent mem- 
brane, very capable of extension and of contraction. The trunks 
generally go deeply through the substance of the gland, and are tor- 
tuous, but do not anastomose laterally with one another ; whence it 
happens that the lobes and lobules of the gland are arranged into 
sections, each of which has its appropriate excretory duct. In order 
to make a complete injection of the gland, each sinus must be sepa- 
rately injected through its conoidal tube. This rule is not of uni- 
versal application, as in some experiments performed by the elder 
Meckel upon women advanced in pregnancy and during lactation, 
he succeeded in forcing mercury through one sinus, by its ramifica- 
tions, into those of another : this route was supposed to have been 
through the finest extremities of the ducts. The whole gland itself 
may, however, from the infrequency of this circumstance, and from 
the difficulties and partial condition of these anastomoses, rather be 
considered as a congeries of smaller glands kept distinct by the in- 
terposition of cellular substance between their lobes ; but joined, in 
one respect, by having the terminations of their excretory tubes col- 
lected into one bunch in the nipple. This latter circumstance 
seems to be only a provision for the more convenient sucking of the 
infant. 

The excretory ducts are no where furnished with valves, which 
accounts for the facility with which they may be injected backwards 
from the nipple. An opinion was entertained by Haller, and by 
other anatomists after him, that some of these ducts originate in the 



148 



LACTIFEROUS GLANDS. 



surrounding cellular substance, but this has been refuted by the re- 
searches of Cubolo. Some anatomists have thought that there is a 
direct communication between the ends of the lactiferous tubes and 
the arteries, veins, and lymphatics. Mascagni, after a very success- 
ful injection of the gland, whereby its vesicles were filled with quick- 
silver, not meeting with such an occurrence, was induced to think 
that when the communication did happen, it was produced by 
rupture. 



Fig. 30. 



Fior. 31. 





Terminal follicles of 
Mammary gland, with 
their secreting cells, a, 
a,- — b, b, the nuclei. 



Terminal extremities 
of milk-duct in follicles ; 
from a mercurial injec- 
tion, by Sir A. Cooper ; 
enlarged four times. 



The membrane of the lactiferous canals is somewhat yellow, and 
upon a transverse section of the gland may be distinguished by its 
colour. It is covered by epithelial cells, which are almost every 
where pavement like, according to Pappenheim ; upon their removal 
he found transverse elastic fibres, covered with longitudinal fibres 
and numerous cellular fibres, but no muscular. 



Tlie Areola, 

In virgins is a rose-coloured circle, which surrounds the base of 
the papilla or nipple. In women who have borne children, or in 
those whose age is advanced, it becomes of a dark brown. The 
skin of the areola is extremely delicate, and on its surface, particu- 
larly in pregnant or nursing females there are from four to ten tuber- 
cles, which sometimes form a regular circle near its circumference, 
and in other subjects are irregularly distributed. Each of these 
tubercles has near its summit three or four foramina, which are the 
orifices of the excretory ducts of a little gland forming the tubercle. 
The areola consists of a spongy tissue beneath which there is no fat ; 



AREOLA. 149 

it is susceptible of distention during lactation, or from particular ex- 
citement. 

The greater number of anatomists have considered these tuber- 
cles as intended only for the secretion of an unctuous fluid which 
lubricates the areola and nipple, and protects them from excoriation 
by the sucking of the infant. It is said, however,* that when some 
time has elapsed after a repast, or when there has been a long inter- 
val to the nursing of the child, milk flows from them abundantly ; 
but that in reverse circumstances a transparent, limpid fluid is dis- 
tilled in small drops ; all of which would tend to prove that they are 
of the same nature with the mammae themselves, being only smaller. 
In addition to them, it is said that the areola and the nipple are 
furnished with a great number of sebaceous glands, which do not 
elevate themselves above the surface, and which may be found on 
and near the tubercles* 



The Papilla, 

Is the truncated cone in the centre of the mamma, of the same 
colour with the areola, and surrounded by it. The lactiferous tubes 
terminate on its extremity. It is collapsed and in a very pliable 
state for the most part, but when excited it swells, becomes more 
prominent, and of a deeper colour. Its skin is rough, and provided 
with numerous and very small papillae. Its internal structure con- 
sists of the extremities of the lactiferous tubes united by condensed 
cellular membrane. 

The mamma is supplied with blood from the external thoracic, 
intercostal, and the internal mammary arteries. Its veins attend 
their respective arteries. The nerves come from the axillary plexus 
and from the intercostals. The lymphatics run into the internal 
mammary, intercostal, and axillary trunks. 

Among the anomalies affecting this gland is the existence of a 
supernumerary nipple — but sometimes there is a second gland entire 
on one or both sides, and commonly placed below the normal one. 

* J. F. Meckel, 

Vol. II.— 14 



BOOK VII. 



OF THE ORGANS OF RESPIRATION. 

The Organs of Respiration are the Larynx, the Trachea, and the 
Lungs. 



CHAPTER I. 

Of the Larynx.* 

The Larynx is an irregular cartilaginous tube that forms the uppei 
extremity of the windpipe. It is situated immediately below the os 
hyoides and the root of the tongue, where it may be felt readily 
through the integuments, and by its prominence contributes to the 
outline of the neck. Its position is such, that it is bounded behind 
by the pharynx, which is interposed between it and the vertebras of 
the neck; and laterally by the primitive carotid arteries and the in- 
ternal jugular veins. It gives passage to the air which is inhaled 
into the lungs or exhaled from them, and also contributes essentially 
to the production of the voice. Its special use, on the latter oc- 
casion, has induced some anatomists to give it a description apart 
from that of the other organs of respiration ; but as the function of 
voice is subordinate to that of respiration, I have preferred an ob- 
servance of its most natural and local connexions. 

Five distinct cartilages form the skeleton of this structure : the os 

* Anat. Atlas, Figs. 411 to 424, inclusive. 



152 ORGANS OF RESPIRATION. 

hyoides, which is common to it and to the root of the tongue, also 
contributes to its superior part, in a manner which will be presently 
mentioned. The cartilages are one Thyroid, one Cricoid, one 
Epiglottis, and two Arytenoid. 

The Thyroid Cartilage (Cartilago Thyroidea) is the largest of the 
five, and being placed about one inch below the os hyoides, pro- 
duces in the upper part of the neck the prominence called Pomum 
Adami. It consists in two lateral halves, which in most individuals 
are perfectly symmetrical, and are continuous with each other on the 
middle line of the body. These two sides form at their line of junc- 
tion an angle projecting forwards, and resembling that of the canal 
or hydraulic gate : the superior part of the angle is more prominent 
than the inferior; particularly in the male subject. The sides of 
this body lean outwards, by which its transverse diameter above is 
increased. 

The angle is terminated above by a deep notch, from which the 
superior margin begins to form a curvature, on either side, like the 
letter S; the inferior margin is also somewhat curved, but to a 
smaller degree. The posterior margin of each half is nearly 
straight, but is elongated above, with the aid of the upper margin 
into a long process, the Cornu Majus; and below with the aid of 
the inferior margin, into another process not so long, Cornu Minus. 
The internal surface of each half of the thyroid cartilage is flat; 
but the exterior surface is slightly marked by the sterno-thyroid and 
the thyreo-hyoid muscles. 

The Cricoid Cartilage [Cartilao-o Cricoidea) is placed below the 
thyroid, and is the base of the larynx. It is an oval ring, of an un- 
eo L ual thickness and breadth. 

Its inferior margin is nearly straight and horizontal, and is con- 
nected to the first ring of the trachea ; it is also thinner than the 
superior: the latter is very oblique, and rises from before backwards 
and upwards so abruptly, that the breadth of the cricoid cartilage 
behind becomes three times as great as it is in front, under the in- 
ferior margin of the thyroid cartilage. The superior margin has on 
each side, behind, a little head, or convexity, which receives the 
base of the corresponding arytenoid cartilage, and forms with it a 
ball and socket joint. 

The interior surface of the, cricoid cartilage is smooth, and co- 



THE LARYNX. 153 

vered by the lining membrane of the larynx. Its exterior surface is 
flattened behind on each side, by the posterior crico arytenoid mus- 
cles ; it is marked also laterally by other muscles, and by the infe- 
rior cornu of the thyroid cartilage. 

The cricoid cartilage is embraced by the inferior margin of the 
thyroid, but in such a way that a triangular interval is left in front 
between the two cartilages. 

The Arytenoid Cartilages (CartUagines Jlrytcenoidece) resemble 
triangular pyramids curved backwards, and are about six lines long. 
They are placed on the upper margin of the cricoid cartilage be- 
hind. The anterior face of each is uneven, and divided into two 
concavities ; the posterior face forms a single cylindrical concavity ; 
and the internal face, by which it approximates its fellow, is nearly 
flat. When joined together, the two cartilages resemble the mouth 
or spout of a pitcher, from whence their name. Their bases are 
hollowed into a small glenoid cavity, for articulating with the cricoid 
cartilage. 

A synovial capsule is reflected over the articulation, between the 
arytenoid and the cricoid cartilage : this capsule is strengthened by 
a few scattered ligamentous fibres. 

The Epiglottis Cartilage (Epiglottis) is situated on the posterior 
face of the base of the os hyoides, being enclosed partially by the 
two sides of the thyroid cartilage. Its general form is that of an 
oval disk ; the upper margin of it is thin and rounded, partially 
curled forwards, and the lower part is elongated into a pedicle 
which adheres to the entering angle of the thyroid cartilage. Its 
lateral margin is attached by a thin elastic membrane to the entire 
length of the upper thyreo arytenoid ligament. 

Its surfaces, though nearly flat, are not fully so ; for, anteriorly, 
it forms a cylindrical convexity, and posteriorly, a cylindrical con- 
cavity, from side to side. When nicely stripped of its covering, a 
number of very small foramina is seen to exist in it, which are 
considered to give passage principally to the ducts of muciparous 
glands. Its connexions, aided by its natural elasticity, keep it in a 
vertical attitude behind the base of the tongue ; its rounded margin 
is elevated above the latter, and overlooks it. 

In addition to the preceding cartilages, there are always two, and 

14* 



154 ORGANS OF RESPIRATION. 

sometimes four others. On the top of each arytenoid is to be found 
one, {Corniculum Laryngis;) it is somewhat triangular and elongated: 
its inferior face is attached bv a few ligamentous fibres to the end 
of the arytenoid ; it is included in the soft parts, and is very move- 
able. The others, when they exist, which is rare, are found on the 
margin of the glottis, in the duplicature of the membrane which is 
extended from the side of the epiglottis, to the tip of the arytenoid 

cartilage. 

I 

From the whole superior margin of the thyroid cartilage included 
between its greater cornua, there proceeds upwards a thin lamina of 
somewhat condensed cellular substance, which is attached to the 
inner margin of the base and of the cornua of the os hyoides their 
whole length. It fills completely the space between the os hyoides 
and the thyroid cartilage. This membrane is called the middle 
Thyreo-hyoid Ligament, [Ligament Thyreo-Hyoid. .Medium,) though 
its ligamentous character is by no means well developed. It com- 
pletes the periphery of the larynx in the space alluded to, and, from 
its thin yielding nature, presents no obstacle to the motions of the os 
hyoides and of the thyroid cartilage upon each other. 

The posterior margin of this membrane, on each side, is bounded 
by a long, rounded, fibrous chord, the Lateral Thyreo-Hyoid Liga- 
ment, (Ligamentum Thyreo-Hyoideum Laterale.) The latter is ex- 
tended from the cornu major of the thyroid cartilage to the tubercu- 
lated extremity of the os hyoides, and frequently contains, about its 
centre, a small oval cartilage or bone, (Cartilago Triticea,) not 
quite so large as a grain of wheat. 

Immediately under the body of the os hyoides, between its con- 
face and the middle thyreo-hyoid ligament, is a small sac or 
cell formed between the lamina? of this ligament, and frequentlv ex- 
tending itself downwards as far as the notch of die thyroid cartilage, 
it is flat, about four or five lines in its transverse diameter, and pre- 
sents a shining surface. I have never seen a fluid in it in the na- 
tural state; its secretion, however, sometimes becomes excessive, 
and it is then elongated downwards over the front of the thyroid and 
of the cricoid cartilage, as far as the isthmus of the thyroid gland. 
In this state it frequently forms a small fistulous opening, at its lower 
end, through the skin ; and which is marked by a fold of the latter 
across the neck. The true pathology of the disease was first pointed 
out by the late Dr. Physick, who cured it, in some cases, by the in- 
troduction of lunar caustic, and in others by extirpation. 



THE LARYXX. 155 

The lateral Crico-Thyroid Ligament attaches the Cornu minus or 
inferior horn of the thyroid cartilage to the side of the cricoid ; there 
is not unfrequently an articular cavity within its circle. This junc- 
tion is the centre of the very limited rotatory motion of die thyroid 
upon the cricoid cartilage. 

The interval in front between the thyroid and the cricoid cartilages 
is filled by a ligament adhering to its margins called the Middle 
Crico-Thyroid, to distinguish it from the ligamentous junction be- 
tween the inferior cornua of the thyroid, and the sides of the cricoid. 
The middle ligament has some small apertures in it for the passage 
of blood vessels and of nerves. It is the part commonly cut in the 
operation of laryngotomv. 

The Thyreo-Aiytenoid Ligaments are two in number, on each 
side of the larynx ; one above the other, at the distance of three 
lines. The inferior is extended from the anterior angle of the base 
of the arytenoid cartilage to the inferior part of the entering angle of 
the thyroid, and, by converging towards its fellow, is inserted there 
in contact with it. Its fibrous structure is very distinct. It also 
bears the name of vocal chord (Ligamentum Vocale,) from its border- 
ing the rima glottidis. The superior thyreo-arytenoid ligament arises 
from the middle of the anterior edge of the arytenoid cartilage, and is 
also inserted into the entering angle of the thyroid ; it is more distant 
from its fellow than the lower one is, and goes almost parallel with 
it ; so that the opening between the two upper is both larger and 
more like an oblong, than it is between the two lower. Its fibrous 
structure is less distinct than that of the lower. Both the upper and 
the lower ligaments are covered by a reflection of the lining mem- 
brane of the larynx, and are small, roimd fibrous bands, which are 
rendered more or less tense by the action of the small muscles of the 
larynx. 

The superior thyreo-arytenoid ligament is attached, in its whole 
length, by a triangular fibro-muscular layer to the pedicle and side of 
the epiglottis : the posterior margin of this layer is distinctly mus- 
cular, and must have the effect of drawing the ligament upwards, 
hence this ligament is in an arched line. 

Lauth has described a band of radiating elastic fibres which leaves 
the thyroid cartilage, between the vocal chords, and expands so as 
to be attached to the superior margin of the Cricoid cartilage, — to 



156 ORGANS OF RESPIRATION. 

the crico-thyroid ligament, — to the arytenoid cartilage and its articu- 
lation, — and also to the lower and upper thyreo-arytenoid ligaments.* 
There are several pairs of muscles belonging to the larynx. 

1. The Thyreo-Hyoideus, as observed in the former account of 
this muscle, looks like a continuation of the sterno-thyroideus. It 
arises, obliquely, from the side of the thyroid cartilage by the ridge, 
there ; and running upwards, it is inserted into a part of the base, 
and into nearly all the cornu of the os hyoides. 

When the thyroid cartilage is fixed, it draws down the os hyoides; 
but when the latter is fixed, it draws up the thyroid cartilage. 

2. The Crico-Thyroideus arises, tendinous and fleshy, from the 
anterior lateral surface of the cricoid cartilage, and passes upwards 
and backwards, to be inserted into the inferior cornu of the thyroid 
cartilage, and into the adjacent part of its inferior edge. 

Use, to draw these cartilages obliquely together. 

3. The Crico-Arytenoideus Posticus arises from the back of the 
cricoid cartilage, occupying its excavation, and is inserted into the 
posterior part of the base of the arytenoid cartilage. 

It draws the arytenoid backwards, and makes tire ligaments tense. 

4. The Crico-Arytenoideus Lateralis arises from the side of the 
cricoid cartilage, and is inserted into the side of the base of the ary- 
tenoid. 

Use, to draw the latter outwards, and open the chink of the 
glottis. 

5. The Thyreo-Arytenoideus arises from the posterior face of the 
thyroid cartilage, near its angle, and the middle crico-thyroid liga- 
ment, and is inserted into the anterior edge of the arytenoid cartilage. 

Use, to relax the ligaments of the glottis. 

6. The Arytenoideus Obliquus arises from the base of one ary- 
tenoid cartilage, and is inserted into the tip of the other. It is a 
very small fasciculus, and sometimes only one muscle exists. 

Use, to close the chink of the glottis. 

* HuschkeTraitedeSplanch.p.22J. Paris, 1845. Also Midler Physiol, p. 
1005, who considers that an extension or lamina of the same, covers the outer 
face of the ventricle of the Larynx. 



THE LARYNX. 157 

7. The Arytenoideus Transversus is always a single muscle which 
arises posteriorly from the whole length of one arytenoid cartilage, 
excepting a little part of the tip, and is inserted, in a corresponding 
manner, into the other. It fills up the cylindrical concavity of the 
arytenoid cartilages. 

Use, to close the chink of the glottis. 

8. The Thyreo-Epiglottideus consists in a few fibres, and arises 
from the posterior face of the thyroid cartilage near its entering angle. 
It is inserted into the side of the epiglottis. 

Use, to draw the epiglottis downwards. 

9. The Aryteno-Epiglottideus consists also in a few indistinct 
fibres, and arises from the superior lateral parts of the arytenoid car- 
tilage. It is inserted into the side of the epiglottis. 

Use, to draw the epiglottis downwards. 

These last two muscles are generally so small and undefined, that 
they cannot be satisfactorily distinguished from the adjacent soft 

parts. 

On the posterior face of the thyroid cartilage ; of the middle thyreo- 
hyoid ligament ; and on each side of the epiglottis cartilage, surroun- 
ding its lower part with the exception of its posterior face, there is 
an accumulation of cellular and adipose substance. In the lower 
part of this substance there are several small glandular bodies, some- 
times insulated and sometimes collected together, which are con- 
sidered to detach their prolongations into the foramina of the epi- 
glottis cartilage, and seem to open thereby on its laryngeal surface ; 
they are mucous glands. 

The Arytenoid Gland, which is also muciparous, is situated in 
front of the arytenoid cartilage, in the duplicature of the mucous 
membrane which passes from the side of the epiglottis cartilage to 
the arytenoid. It is a small body of a grayish colour, resembling 
the letter L, and consists in distinct grains ; it is supposed to have 
iis excretory ducts opening into the larynx. It is frequently 
wanting. 

The Interior Face of the Larynx is lined by a mucous membrane, 
continuous above with that of the mouth and pharynx, and below 



158 ORGANS OF RESPIRATION. 

with that of the trachea. Where it is reflected from the base of the 
tongue to the epiglottis cartilage, it forms, as described, a well- 
marked vertical fold or frsenum in front of the middle of the latter, 
and on each side of this middle fold there is another, not so distinct, 
but varying in different subjects. Beneath the middle fold is a 
strong fibro-muscular connexion with the root of the tongue.* The 
three folds form two pouches in front of the epiglottis, in which food 
is sometimes lodged. The mucous membrane also forms the dupli- 
cature on each side already alluded to, which passes from the lateral 
part of the epiglottis cartilage to the arytenoid of the same side of 
the body. This duplicature forms the superior boundary of the 
cavity of the larynx, and is very soft and extensible, permitting freely 
the epiglottis to be depressed and to rise again into its vertical posi- 
tion. The duplications of the two sides, taken together, form an 
oblong oval opening into the larynx, passing very obliquely upwards 
and forwards to the epiglottis, and terminated behind by a notch 
between the cornicula laryngis. At the latter place the mucous 
membrane is wrinkled and loose, so as to permit, by its extensi-, 
bility, free motion to the arytenoid cartilages. 

After adopting the preceding arrangement, the lining membrane 
of the larynx passes downwards ; it covers smoothly the posterior 
face of the epiglottis, adhering closely to it ; but, when it reaches 
the thyreo-arytenoid ligaments, it is tucked in between the upper 
and the lower one, so as to form, on either side, an oblong pouch, 
the bottom of which is broader than its orifice between the ligaments. 
This pouch is the ventricle of Galen, or of Morgagni, or of the 
larynx;f it projects into the fatty glandular matter on the posterior 
face of the thyroid cartilage, and has its base resting on the thyreo- 
arytenoid muscle. Its superior end reaches almost as high as the 

* A muscle of a triangular shape has lately been observed by the English 
anatomists,* situated in front of the epiglottis, passing to it from the base of 
the os hyoides : it is called Hyo-Epiglottideus. The observations on its ex- 
istence have not yet been repeated sufficiently often to determine whether it 
belongs to the normal structure of the body or not, and in my own dissections, 
for the purpose of ascertaining its existence, it has not occurred. Albinus, 
Soemmering, and others, speak of the occasional existence of muscular fibres 
there. A strong muscle is found there in the lower animals, as stated in the 
description of the tongue, vol. 1st. 

f Anat. Atlas, Fig. 420. 

* Am. Med. Joura. vol. v. p. 475. 



THE LARYNX. 159 

upper margin of the thyroid cartilage, and it has some small fasci- 
culi of muscular fibres on its belly which seem appropriated to its 
use. This pouch is in fact divided into two compartments, an upper 
and lower ; the lower is oblong and horizontal, being between the 
thyreo-arytenoid ligaments; the higher portion is a compressed 
spheriform sac, and communicates with the low T er by a narrow neck. 
The continuation of the lining membrane of the Larynx afterwards 
lines smoothly the cricoid cartilage, and abounds there in mucous 
follicles. 

That portion of the larynx which is formed by the thyreo-aryte- 
noid ligaments, and the pouches between them, is the structure 
essential to the formation of voice. The opening between the two 
lower ligaments, is the Rima Glottidis, and the space between the 
upper ligaments and the duplicature of the mucous membrane pass- 
ing from the arytenoids to the epiglottis cartilage, may be termed the 
Glottis. 

The Epiglottis Cartilage is principally useful in preventing articles 
of food from falling into the glottis, either in swallowing or in vo- 
miting. The strength of its muscles, however, does not seem to be 
sufficient to draw it down over the glottis, as many physiologists 
suppose ; on the contrary, I am induced to believe that the glottis 
is rather drawn upwards to it. If, on any occasion, it be depressed 
or bent down over the glottis, the position must be caused by me- 
chanical pressure from the bulk of the article swallowed. But the 
latter explanation is not sufficient to account for the swallowing of 
fluids, or of a very small body as a pill or a crumb of bread. 

Impressed with these objections, and unsatisfied with the com- 
mon theory, I had an opportunity, in a dissection many years ago, 
of witnessing a position of these parts which afforded a satisfactory 
explanation. The subject was a robust, muscular man, who had 
died suddenly. The upper orifice of the glottis was closed and pro- 
tected, but by an arrangement precisely the reverse of the received 
opinion ; for the epiglottis, retaining its naturally erect position, with 
a slight inclination backwards, had the opening of the glottis drawn 
up so as to come in contact with its posterior face. The cricoid 
cartilage, as has been mentioned, slopes on its superior margin up- 
wards and backwards ; the front surfaces of the arytenoid cartilages, 
in their natural position, are nearly on a line with this slope, or a 
continuation of it ; the whole may, therefore, be considered in the 
light of an oblique plane, rising up behind the epiglottis cartilage. 



160 ORGANS OF RESPIRATION. 

By a very slight additional elevation of this plane along with the 
rotatory motion of the thyroid cartilage upon its lesser cornua, the 
plane is caused to come in contact with the posterior face of the 
epiglottis, and thereby to close the upper opening of the glottis. 

The principal agents in this motion are the thyreo-hyoid muscles, 
the contraction of which, causing the larynx to ascend, the opening 
of the glottis is brought up behind the epiglottis, and thereby secured 
from the introduction of food into it. Whether the food be passed 
from the mouth into the stomach, as. in swallowing, or from the sto- 
mach into the mouth, as in vomiting, is equally unimportant ; and 
the security is the same, whether the article be small or large, fluid 
or solid. Several years ago, I dissected a gentleman who had 
symptoms of sore throat with swelling of the neck, superadded to 
those of pulmonary consumption : during the existence of his sore 
throat, in addition to the usual difficulty of swallowing, he was fre- 
quently affected in the act, with strangulation to an alarming and 
distressing degree. In the dissection, it was found that an abscess, 
of considerable extent, existed between the os hyoides and the thy- 
roid cartilage, and involved the thyreo-hyoid muscles. Without 
knowing at the time the value of this observation, I am now per- 
suaded that the strangulation arose from the inactivity of the thyreo- 
hyoid muscles. In some ulcerations of the epiglottis cartilage which 
I have had an opportunity of seeing; the upper circular portion which 
projects above the root of the tongue, has been lost; if the accident 
be confined to that extent only, deglutition is not impaired, because 
still enough of the epiglottis is left to perform the office assigned to it, 
as the upper part is less essential. The cases of its reputed loss by 
wounds, must be considered as applying themselves to this upper 
portion only, because a wound low enough to remove the whole 
body, would cause such a destruction of the rima glottidis, as to pro- 
duce an embarrassment of respiration, incompatible with life. 

It is probable that the inferior constrictors of the pharynx, as well 
as the stylo-pharnygeal muscles, assist in this use of the thyreo- 
hyoidei. 

There is a well-marked difference in the larynx of the two sexes. 
In the female, it is generally smaller by one-third than it is in the 
male ; the thyroid cartilage is also less prominent, in consequence of 
its two halves uniting at an angle more obtuse the pomum Adami is ; 
therefore, seldom conspicuous. The rima glottidis is also smaller in 
women. 



THE TRACHEA. 161 

The nerves of the larynx come principally from the superior and 
and the inferior laryngeal branches of the par vagum. 



CHAPTER II. 
Of the Trachea, and the Glands hordcring upon it. 

SECT. I. — THE TRACHEA. AND BRONCHIA.* 

The Trachea, or Aspera Arteria, is a cylindrical canal of four or 
five inches in length and about nine lines in diameter, communica- 
ting with the lungs for the transmission of air. It opens into the 
larynx above, by being attached to the inferior margin of the cricoid 
cartilage, and terminates in the thorax, opposite the third dorsal 
vertebra, by two ramifications called Bronchia. In this course it is 
situated over the middle line of the neck, beneath the sterno-thyroid 
muscles, and separated from them by the deep-seated fascia of the 
neck and the adipose matter beneath it. It is placed in front of the 
oesophagus, between the primitive carotid arteries and the internal 
jugular veins. When it has got into the thorax, it inclines slightly to 
the right side as it passes behind the curvature of the aorta. Of its 
two branches, the right bronchus is larger than the other ; it is also 
less slanting, and an inch long before it divides ; it sinks below the 
right pulmonary artery, to penetrate the lung about the fourth dorsal 
vertebra. The left bronchus being an inch longer sinks into the 
lung of the left side, below the corresponding pulmonary artery, and 
opposite the fifth dorsal vertebra. The bronchia then divide and 
subdivide very minutely through the lungs. 

Very dissimilar structures enter into the composition of the 
trachea; they are cartilage, ligamentous fibre, muscle and a mucous 
membrane. 

* Anat. Atlas, Figs. 429, 430. 
Vol. II.— 15 



162 ORGANS OF RESPIRATION. 

The Cartilage preserves the cylindrical shape of the trachea, and 
consists in from sixteen to twenty distinct rings, which are deficient 
in the posterior third of their circumference. Each ring is about 
two lines broad, and half a line thick, and is kept apart from the one 
above and below it by a small interstice : sometimes, however, they 
run into each other. 

There is an almost uniform similitude between these rings ; the 
principal departure from which is observed in the first being rather 
broader in front than the others, and in the last ring, which, by its 
corset-like shape in front, contributes, to the beginning of each 
bronchus. 

The rings of the Bronchia, are like those of the trachea, deficient 
in their posterior third, and the same arrangement holds during 
their primitive ramifications in the lungs. But as they subdivide 
more and more, the cartilages do not succeed each other so closely, 
and are smaller segments of circles ; they are also not regularly de- 
ficient at the posterior third ; but in place of the latter, the bronchial 
ramification is furnished with cartilage, consisting in several pieces 
put end to end. The pieces become, afterwards, more and more 
scattered and smaller, till they finally disappear, and the bronchus 
is simply membranous. At the orifice of each branch of the bron- 
chia, there is a semi-lunar cartilage, forming rather more than one 
half of its circumference, and having its concave edge upwards : 
the whole arrangement resembles somewhat the pasteboard to an 
eared bonnet, and is evidently to keep the orifice open. 

The Ligamentous Structure of the trachea and of the bronchia is 
very evident between the proximate margins of the cartilaginous 
rings, and fills up the intervals between them so as to make the tube 
perfect. This tissue may be traced over the surfaces of the rings, 
forming their perichondrium, so that they may be considered as im- 
bedded in it. It does not exist in the same state, in the human sub- 
ject, in the interval behind ; where a third of the ring is defective, 
its place being supplied by a condensed cellular substance approach- 
ing to a fibrous character and intertexture ; but in the bullock it is 
there also. In the smaller ramifications of the bronchia, where the 
several little cartilaginous segments, are interposed around it ; it is 
probable that this tissue contributes to the whole periphery of the 
ramification. 

This ligamentous structure possesses great elasticity, which is 



THE TRACHEA. 163 

manifested by the rapid shortening of the trachea, when its two ex- 
tremities are stretched apart and then suddenly let loose. And it is 
the continuance of this quality of elasticity, in the minute ramifica- 
tions of the bronchia, which proves the existence of this tissue there, 
even when it cannot be very distinctly seen. 

The Muscular Structure of the trachea exists at the cartilaginous 
deficiency in its posterior third, and consists in a thin muscular 
plane 1 whose fibres pass transversely between the interrupted ex- 
tremities of its cartilaginous rings. These transverse fibres begin at 
the first ring, and exist all the way down : they arise from the in- 
ternal faces of the rings, and the intermediate elastic ligamentous 
tissue ; about a line beyond their extremities. Anteriorly, they are 
covered by the lining membrane of the trachea, and posteriorly, by 
the dense cellular tissue just spoken of. 

A similar arrangement of muscular structure occurs in the bron- 
chia and for some distance into the lungs. Where the cartilages 
become scattered and irregular, the muscular fibres are said, by 
J. F. Meckel, and by M. Reisseissen,* to perform the whole circuit 
of the bronchial ramification, and to be visible even beyond the 
existence of the cartilaginous pieces. Soemmering expresses a doubt 
of this arrangement.! It is very difficult in such minute structure to 
arrive at a satisfactory conclusion; careful observations, latterly made, 
have, however, induced me to adopt the same conviction as Reis- 
seissen. Longitudinal muscular fibres are said by Portal to exist 
between the contiguous margins of the cartilaginous rings, but the 
fact is far from being ascertained. J 

In some subjects a very strong plane of longitudinal muscular 
fibres, is seen going the whole length of the trachea on its posterior 
face : being placed just behind the transverse muscular fibres. 

* De Fabrica Pulmonis. Berlin, 1822. M. Laennec says (Traite, de l'Aus- 
cultation, Paris, 182G, vol. ii. p. 189,) that he has sought in vain to verify 
these observations of Reisseissen, but that the manifest existence of circular 
fibres upon branches of a middling' size and the phenomena of many kinds 
of asthma, induce him to view, as a thing- well established, the temporary oc- 
clusion of the small bronchial ramifications, by a spasmodic contraction of 
their parietes. 

f Extimae autem ver'postica? ejus fibrae per longitudinem, a cartilagine cri- 
coidea ad pulmones usque descendunt ac, vel in ipsis trachea? ramis haud 
parum conspicui sunt. — De Corp. Hum. Fabrica. 

£ Anat. Med. 



164 ORGANS OF RESPIRATION. 

The use of the muscular tissue has been pointed out, by the late 
Dr. Physick, as follows: — "In expectoration, it diminishes the 
caliber of the air tubes, so that the air having to pass out with in- 
creased rapidity through them, its momentum will bring up the in- 
spissated fluid which may be in its way." This very ingenious 
theory has subsequently been advanced by M. Cruveilhier, of Paris, 
possibly without a knowledge of his having been anticipated ; but 
certainly not without the claims of the eminent individual to whom 
we owe it, having been established by its publication.* 

The mucous Membrane of the trachea lines its whole interior 
periphery, from the larynx to the bronchia, and is continued, under 
the same circumstances, through the latter to their minute divisions. 
It adheres very closely to the contiguous structure, and is continued 
in the substance of the lungs, beyond the traces of any of the other 
tissues which compose the bronchia ; it indeed terminates in the air 
cells. It is very vascular, like other mucous membranes: and also, 
like them, the venous appears to prevail over the arterial vascularity. 
A successful minute injection makes it look as if it consisted of a 
tissue of blood vessels: thin and red, it presents an abundance of 
slightly elevated longitudinal folds : one of the latter, conspicuous 
for its greater size, exists at the commencement of the left bronchus, 
and is yet more developed in the still-born infant. 

The exterior circumference of the mucous membrane is studded 
with Muciparous Glands, about the size of millet seed. These 
glands are particularly conspicuous and abundant on the posterior 
part of the trachea and of the bronchia, where the deficiency of the 
cartilaginous rings is supplied by the musculo membranous structure 
only ; and more of them exist at the lower part of the trachea and 
upon the roots of the bronchia than elsewhere. They are placed 
behind the muscular layer, which their excretory ducts have to 
penetrate. Besides occupying these situations, they are found in the 
interstices between the cartilaginous rings, but here they are much 
smaller. The mucous membrane abounds so much in the orifices 
made by their excretory ducts, that it looks cribriform, which ap- 
pearance is increased by floating it in water. 

About the origins of the bronchia,, there is a considerable num- 
ber of black coloured lymphatic glands, called bronchial, which it 

* Wistar's Anatomy, 3d edition, vol. ii. p. 64 Phil. 1821. 



THE THYKOID GLAND. 165 

is easy to distinguish from the preceding by their colour and much 
greater size. 

There are two more glands of a different character, which, though 
they do not enter into the composition of the trachea, yet from their 
locality, are most conveniently studied at this time : they are the 
Thyroid and the Thymus. 



SECT. II. — OF THE THYROID GLAND.* 

The Thyroid Gland (Glandula Thyroidea) is placed on the first 
and second rings of the trachea, and on the sides of the larynx. 

It consists in a middle, portion which is thin, of variable magni- 
tude in different individuals, sometimes entirely wanting, and which, 
being stretched across the upper part of the trachea just below the 
larynx, is called its isthmus: and of two lobes, one on each side, 
which, being flattened and ovoidal, are extended considerably up- 
wards on the side of the larynx, and downwards on the side of the 
trachea and of the oesophagus. Frequently from the superior part 
of the isthmus, and most commonly on its left side, a small pyramidal 
process runs upwards in front of the cricoid and of the thyroid car- 
tilage, and is attached, by ligamentous fibres to the os hyoides ; this 
process, however, varies much in size and length ; I have never seen 
it double. According to Morgagni and Meckel, the existence of 
this process is much more common than its absence, which corres-. 
ponds with my own observations. The thyroid gland, when ex-* 
tended, measures about three inches from side to side. 

It is covered in front by the sterno-hyoid and thyoid muscles, 
and laterally by the omo-hyoid and the sterno-mastoid. Embracing 
the trachea and the sides of the larynx, its lobes repose upon the 
primitive carotids, and the internal jugular veins. 

The thyroid gland has a capsule which is not very easily raised 
up, but serves to give it a polish ; it is also invested by the condensed 
cellular membrane of the part called fascia profunda colli. Its. 
surface is smooth and uniform. It is of a dark brown colour. When, 
cut into or torn, it is seen to consist of several lobules adhering to 

* Anat. Atlas. Fig. 419. 

15* 



166 ORGANS OF RESPIRATION. 

each other ; but this arrangement is not very distinct, except in an 
enlarged or diseased state ; and may be traced most easily by follow- 
ing the course of the large blood vessels, which pass in the inter- 
stices between the lobules. The latter contain many small vesicles, 
or cells filled with a transparent or yellowish and somewhat unctuous 
fluid : the cells are frequently in a collapsed state, which prevents 
them from being manifest to the naked eye. According to the ob- 
servations of Mr. Simon,* these vesicles are completely closed, being 
formed by a delicate homogeneous membrane, invested by a close 
capillar}- network. Intermixed with their contained fluid are cyto- 
blasts which float freely about, in it. These are found frequently 
as the nuclei, of cells of the diameter of 1-1400 of an inch. 

There are four considerable arteries which supply this body, two 
on each side, one coming from the external carotid and the other 
from the subclavian. The veins follow the course of the arteries 
for the most part. Bichat has made a very interesting remark on 
the subject of its blood vessels; that, notwithstanding their size and 
number, and minute ramifications in it, much less blood remains in 
its capillary system than in that of the liver or kidney, as is proved 
by the quantity of water it tinges in maceration ; he, therefore, infers 
that the capillary system is less abundant. 

Anatomists have sought in vain for one or more excretory ducts 
to this body, and some have imagined that they had found them ter- 
minating in the trachea, or in the larynx. Santorini considered the 
pyramidal process from the isthmus as the desired duct. The em- 
physema with which the gland has sometimes been affected, was 
supposed to be a proof of its communicating with the trachea by ex- 
cretory tubes : but it is more probable that the air was forced into 
the cellular substance, uniting its lobules, and not into the structure 
itself of the gland. 

The settled opinion now seems to be, that whatever fluid it secre- 
tes is conveyed away by the lymphatic vessels. Meckel has sugges- 
ted, that as this gland is more voluminous proportionately in early 
infancy, particularly its pyramidal process, possibly the duct may 
be obliterated when the gland begins to be restrained in its growth; 
but, if this were the case, the duet ought to have been found during 
the period indicated. The probability is, that it is a diverticulum 
of blood from the salivary glands during the intermittence of their 

* Phil. Trans. 1844. 



THE THYMUS GLAND. 167 

action ; and from the marked sympathy between it and the brain in 
goitre, it may exercise a corresponding function on this organ during 
its intervals of repose. 

Duverney* has described a small azygous muscle on the middle 
line of the body, coming from the under margin of the base of the 
os hyoides, and running over the middle of the thyroid cartilage, to 
be inserted mto the upper margin of the isthmus of the thyroid gland. 
Soemmering calls it Levator Glandulse Thyroideae, and speaks of it 
as being found more frequently on the left side, and about half of the 
breadth of the thyreo-hyoideus. After many special examinations 
for it I have found it in but few instances; I, therefore, consider it 
rare ; though without a close attention to structure, the pyramidal 
process of the isthmus of the gland may, from the similitude of colour 
and position, be very readily mistaken for it, which I have reason to 
believe has been frequently the case.f Some few fibres are often 
found going to the isthmus of the gland from the crico-thyroid, and 
the thyreo-hyoid muscles, or from the thyroid cartilage. 



SECT. III. — OF THE THYMUS GLAND J 

This body {Glandules Thymus) is placed between the trachea and 
the upper extremity of the sternum. It is irregularly triangular, its 
broadest part being above,, and the narrower below. In the adult, 
it is in a collapsed and shrivelled state, and scarcely presents a ves- 
tige of what it once was ; it is, therefore, only in the infant that it 
can be satisfactorily studied. 

At birth, it is much larger, not relatively, but actually, than it is 
in the adult, and extends from the body of the heart up to the thy- 
roid gland. It is of a very soft consistence and of a pink colour. 
It is surrounded by a capsule of cellular substance, which, when re- 
moved, permits the gland to be resolved into two lobes, one on 
either side, which adhere to each other. These lobes may be sepa- 

* Essai D'Anatomie en tableux imprimes, pi. IV. Paris, 1745. 

f The unassisted eye, in a strong light, is generally sufficient to determine 
the structure ; but in case of doubt, by boiling the gland, if there be muscular 
fibres along this process, their longitudinal and parallel direction will become 
evident; they also may then he torn asunder, so as to be made still more dis- 
tinct; whereas, the vesicular structure of the gland is not susceptible of divi- 
sion into fibres. 

X Anat. Atlas, Fig. 426. 



168 ORGANS OF RESPIRATION. 

rated with facility into lobules, which contain a whitish cream-like 
fluid. 

A good Essay on the structure of this gland, has been published 
by the distinguished British surgeon and anatomist, the late Sir 
Astley Cooper,* illustrated by excellent plates. From this it ap- 
pears that the lobules of the gland are formed of vesicles of various 
sizes, discharging into pouches at the base of the lobules, and they 
again discharge into a duct or common reservoir, which runs from one 
end of the gland to the other, the consistence of which duct is extreme- 
ly feeble. This duct, the pouches, and the vesicles, may be filled with 
an injection, by means of a pipe introduced into the substance of the 
gland. A large lymphatic trunk passes from the gland, on each side, 
into the transverse vein near its junction with vena innominata of the 
right side or at the junction itself. 

The observations of Sir Astley Cooper, have been confirmed in 
their main features, by those within two or three years past of Dr. 
Oesterlin of Jena, and of Mr. Simon of London, who also assert that 
the cream-like fluid of the vesicles is mixed with a multitude of cor- 
puscles, having the structure and relations of nuclei. Many of the 
corpuscles are circular, but others are flat and disk-like. Their ave- 
rage diameter is about the 1-3839 of an inch, and they are charac- 
teristically dotted with from two to five very small dark spots, which 
are either collected or dispersed.! 

Sir Astley thinks, or, rather, asks, whether this gland does not 
prepare a fluid for foetal nourishment, in the absence of proper chyli- 
fication, during fetal life ? inasmuch as all the elements of the blood 
are upon chemical analysis, found in the fluid contained in its cavi- 
ties. 

It is visible in the third month of gestation, and continues to grow 
till the end of the second year of extra-uterine life. It then collapses, 
and its structure is effaced about the twelfth year ; its remains are 
scarcely distinguishable subsequently from the surrounding cellular 
substance. It is stated by Krause| that in almost all individuals of 
from twenty to thirty years of age, in whom he has examined the con- 
dition of this gland, it was still existing, and in some instances, larger 
than in children ; and that in persons of from thirty to fifty years he 
had found it of considerable size. It has latterly happened to me to 

* London, 1832. 

f Br. and For. Med. Review. April, 1846. 

X Midler's Physiology, p. 622. 



THE LUNGS. 169 

see it in two persons of from twenty to thirty years old, forming an 
oblong oval body, two inches or more long by twelve or fifteen lines 
wide, and preserving its characteristic structure and division into 
lobes and lobules. No excretory duct has been found for it, unless 
we may consider as such the lymphatic trunk alluded to by Sir 
Astley Cooper. Though it clearly belongs to foetal and infantile 
existence, its use is problematical. The probability is, that it is a 
diverticulum of blood from the lungs during their state of quiescence 
in foetal life, and until their structure becomes confirmed and propor- 
tionately evolved. 



CHAPTER III. 

Of the Lungs.* 

The Lungs (Pulmones) are the essential seat of the process of 
respiration, and occupy the greater part of the cavity of the thorax, 
as formed by the ribs and the intercostal muscles on the sides ; by 
the sternum and its cartilages in front, by the dorsal vertebras behind, 
and by the diaphragm below. They are two bodies, placed one on 
either side of the thorax, and separated from each other by the heart 
and its great vessels. As the heart is the only organ of much volume 
which is also included in the cavity of the thorax, the size of the 
lungs is in a direct relation with the capacity of the latter ; and may, 
therefore, be known by external indications in the living body. It 
is probable that there is no void, or only a very small one, between 
the sides of the lungs and the sides of the thorax. 

Each lung forms an irregular cone, the apex of which is above, 
and the base below ; the latter, from resting upon the diaphragm, is 
consequently, oblique from before backwards and downwards, and 
is also concave. The surface which reposes against the periphery 
of the side of the thorax, is, uniformly, rounded ; but that which 
looks towards its fellow, is concave, from being pressed in by the 
heart. The vertical diameter of the lung behind, when it is fully 
distended, goes from the head of the first to that of the last rib, and 
is, from the oblique direction of the diaphragm, consequendy, much 

* Anat. Atlas, Fig. 427. 



170 ORGANS OF RESPIRATION. 

more considerable than the vertical diameter in front, which extends 
only from the first rib to the inferior end of the second bone of the 
sternum, or, in other words, to a level with the tendinous centre of 
the diaphragm. 

The lungs of the adult are of a light pink colour, with specks or 
patches of black ; in early life there is much less of the latter, and 
in advanced life it becomes more abundant. 

The left lung is divided into two lobes by a deep fissure, which 
begins behind, on a level with the fourth dorsal vertebra, and runs 
obliquely downwards and forwards to the anterior margin of its base. 
A deep fissure in a nearly similar situation is observed on the right 
lung ; but from it another fissure branches out forwards, by which 
the right lung is divided into three lobes. The internal face of the 
left lung is also rather more concave than that of the right, from the 
side of the heart projecting into it. The right lung is more volumi- 
nous than the left, which corresponds with the greater size of the 
bronchus on this side, but its vertical diameter is not so great, owing 
to the pressure of the liver from below ; though this diameter is in- 
creased by the descent of the liver when we are upright. 

Near the middle of the internal face of each lung are to be seen 
the points of connexion with the bronchus, and with the pulmonary 
vessels. Before these the anterior margin is thin, and more or less 
winding where the lung is introduced between the heart and the front 
parietes of the thorax. When the lungs are fully inflated, only a 
very small portion of the front of the pericardium can be seen be- 
tween them. The posterior margin is thick, and rounded where it 
rests against the vertebral column. 

The whole rounded circumference of the lung as well as its base, 
though they are in contact with the parietes of the thorax, do not 
adhere at any point to them. The connexion of the lung, constitu- 
ting its Root, as it is called, and by which it is maintained in its 
situation, is entirely on the side of its concave face, where the pul- 
monary vessels and bronchus enter, and though other attachments 
are frequently found springing from different points of the thorax, 
they are purely the results of disease. 



Of the Texture of the Lungs. 

Each lobe of the lungs is divided into a great many distinct lo- 
bules, which adhere together by intermediate cellular tissue. The 



THE LUNGS. 171 

marks of these divisions are apparent on the surface by lines run- 
ning in different directions, but they are made still more distinct by 
tearing them asunder. The Lobules are sub-divided into very fine 
air vesicles or cells, which maybe considered as the dilated termina- 
tions of the ultimate branches of the bronchia, with the same struc- 
ture of an elastic and of a mucous membrane. The opinion is gener- 
ally held, that the cells do not communicate laterally with one another 
as the cells of the bones, but only with the ramifications of the bron- 
chia, to which they respectively belong. Numerous observations 
however, have induced me to abandon this idea, and to conclude 
that the cells of the lobules individually communicate, but not those 
of different lobules. I have succeeded in proving this by distending 
the air cells with tallow, and, after the lung was dried, removing 
the tallow with spirits of turpentine. This process shows the cells 
of their natural size, and communicating freely. A very small por- 
tion of a lung of either the human subject or the calf kept inflated 
and dried shows the same unequivocally.* 

The most prevalent opinion, however, of the day is that derived 
from Willis originally, that the air vesicles have the same relation to 
the bronchioles, that the berries have to the stem in a bunch of 
grapes. This idea has been reiterated by Reisseissen,f and his 
plates fallaciously taken as the standard of structure, in the anato- 
mical works generally. It has also been reasserted still more lately, 
by Huschke under the declaration of the opposite being the repro- 
duction of an ancient error. £ On the contrary, my opinion, sus- 
tained by numerous anatomical preparations, may be traced as far back 
as Helvetius and Duverney, and has as its advocates Haller, Soemmer- 
ing, J. F. Meckel, and Cruveilhier. The doctrine is moreover de- 
cidedly advocated with some modified views, in regard to the shape 
of the cells, by J. M. Bougery, an anatomist now well known for 
his splendid anatomical plates. The leading peculiarity of his views, 
is that the cells, though they communicate freely, are yet canalicular, § 
that is, they have the measurement of length exhibiting great excess 
over every other, in which I do not agree with him. 

In tracing the terminations of the bronchia, in the substance of the 
lungs, the parietes of these canals are observed to become very thin, 

* Anat. Atlas. Fig. 427. from preparation in Anat. Museum. 

f De Pulmon. Struct. 1803. 

t Traite de Splanch. p. 249. Paris, 1845. 

§ Gazette Med. de Paris. July, 1842. 



172 ORGANS OF RESPIRATION. 

and especially after the cartilaginous structure has ceased. The ra- 
mifications or bronchioles seem then to be composed almost entirely 
of a filamentous coat, lined with a delicate mucous membrane. 

The filamentous coat, is no doubt an extension of the membra- 
nous portion existing so conspicuously on the back of the bronchia, 
and it retains the extensibility and contractility of the same. Its 
filaments are principally in a circular direction and resemble so 
strongly muscular fibres, that they alone seem to exist. It is, how- 
ever more probable, that exterior to these, we have a fine elastic 
ligamentous layer, or it may be blended with them, it being difficult 
to distinguish where there is such a sameness of colour, the one 
tissue from the other. Some anatomists, have indeed, considered it 
all as of an elastic ligamentous character, in which case, the circu- 
larity of the fibres, may be compared to the same condition in the 
internal layer of the corpus cavernosum penis. 

The lining mucous membrane of the bronchia is smooth, polished, 
and so thin that it is a mere film, about the thickness and transpa- 
rency of the peritoneum, where it covers a small intestine. Longi- 
tudinal folds may be traced in the length of this mucous membrane 
for some distance down the bronchia, indeed as far as the cartilagi- 
nous segments of circles appear, and even into the finer branches. 
With the aid of a lens, mucous follicles are very perceptible in 
innumerable quantities all over it. It may also be remarked, that 
the bronchia do not end by a regular succession of proportionately 
finer and finer branches ; but that a bronchial trunk, of some lines 
in diameter, sends off in different directions to the contiguous lobules, 
branches about the size of a bristle, which are followed with much 
difficulty, owing to their collapsing: the probability is, however, 
that each one of these branches belongs to a lobule and discharges 
into its cells, in a manner, resembling a blow-pipe fixed to the side 
of a small piece of sponge. In my preparations, these terminating 
tubes of the bronchia, the size of bristles, are seen very distinctly ; 
but there is no appearance of the penicillous arrangement, which would 
be apparent if each cell had its own specific branch of the bronchus 
running to it. 

The internal surface of the lung owing to this multiplication of it 
by cells, may be considered as a vast area obtained in a very small 
space, and containing a close intertexture of the most minute capil- 
laries, for the purpose of exposing the blood to the process of respi- 
ration. 



THE LUNGS. 173 

There is no absolutely uniform size for the air vesicles, but their 
diameter may be stated as from near the two hundredth part to the 
fiftieth of an inch. Weber says from the T |s to T ^. The capillary 
blood vessels have an extremely attenuated distribution over them; 
leaving scarcely any thing like regular interstice, these capillaries 
are in their own diameter, about the twentieth part of the diameter 
of the smaller air vesicles. 

The readiness of pulmonary haemorrhage, is a sufficient proof 
of the facility with which blood passes from the blood vessels into 
the air vesicles and bronchial tubes. An opposite line of commu- 
nication from the air vesicles into the pulmonary blood vessels has 
latterly attracted my attention, and been the subject of several 
experiments, which prove conclusively the certainty of the fact. 
These experiments show that water or air may be injected into the 
air passages of the lungs, and returned by the pulmonary veins, and 
the pulmonary artery, but with especial freedom through the pulmo- 
nary veins.* Whether this is by an absolutely direct communication, 
or by the intervention of the lymphatic system I cannot at present 
determine, but the existing state of my experience is in favour of the 
first. It may, however be stated, that it is a matter of common ex- 
perience with anatomists, to innate the pulmonary lymphatics from 
the air vesicles ; also, to inject the pulmonary lymphatics from the 
bronchial arteries, and therefore, the communication of the air vesi- 
cles with the blood vessels may be by this series of anastomoses ; 
that is going from the air vesicles to the lymphatics, and from them 
into blood vessels, which all communicate freely with one another. 

Besides the ramifications of the bronchia, the substance of the 
lungs is composed of numerous blood vessels and lymphatics, and 
is well supplied with nerves. 

The blood vessels are of two kinds, the pulmonary and the bron- 
chial. The pulmonary artery, coming from the right ventricle of the 
heart, divides under the arch of the aorta into two large branches : 
one for the right lung, and the other for the left. The right branch 
is larger than the left. Each of these branches having reached the 
upper part of the root of its respective lung, begins there to distri- 
bute itself in large trunks, which divide and subdivide throughout 
the substance of the lung. The terminating branches finally become 
capillary, and ramify in the parietes of the air cells, where the blood 

* For the details of Experiments, see Am. Joum. Med. Sc. p. 332. April, 
1843. 
Vol. II.— 16 



174 



ORGANS OF RISPIRATION. 



which they carry, from being dark-coloured and venous, is so altered 
as to have the arterial qualities restored to it, and to become of a 
bright red. From the ultimate branches of the pulmonary artery, 
arise the first branches of the pulmonary veins. These are succes- 
sively accumulated into two large trunks on each side, which, issuing 
at the lower part of the root of the lung, go to open into the left 
auricle of the heart. It has been remarked by Mr. Boyer, that the 
two pulmonary veins, are less capacious than the pulmonary artery 
of the same side, in which they manifest a peculiarity of blood ves- 
sels, differing from what exists in other parts of the body. The 
pulmonary artery and veins are distributed in company with the 
bronchus. From the observations of Professor Mayer, it appears 
that valves exist in the pulmonary veins, contrary to the general 
opinion of anatomists. They are found where smaller trunks join 
the larger ones, at an acute angle ; but there are none where they join 
at a right angle/ 

The second order of blood vessels, being the bronchial, also con- 
sists in arteries and in veins, and are for the nourishment of the 
lungs. They, too, attend the branches of the bronchia. The bron- 
chial arteries pervade the substance of the lung by innumerable fine 
branches, and anastomose with the pulmonary arteries. The bron- 
chial veins also anastomose with the pulmonary veins, but, finally, 
come out in small trunks from the root of the lung; the right one 
empties into the vena azygos, and the left into the trunk of the su- 
perior intercostal veins of the left side about the third dorsal 
vertebra. 



Fig. 33. 




Arrangement of the Capillaries of the air- 
cells of the Human Lung. 



The Lymphatics of the 
lungs are numerous ; after 
traversing the black bron- 
chial glands, those of the 
left side empty into the tho- 
racic duct, and those of the 
right into the large lymphatic 
trunk coming from the upper 
extremity. 

The nerves come princi- 
pally from the par vagum. 
Some of them are distributed 
with the bronchus, and may 
be traced easily far along its 



* Am. Med. Jour. vol. iii. p. 186. 



THE LUNGS. 175 

branches, forming beautiful anastomoses around them : their texture 
there resembles much that of the sympathetic : they are thought to be, 
finally, spent upon the mucous membrane : others seem to be more 
specifically appropriated to the vessels. 

It will now be understood that the root of each lung is formed by 
a pulmonary artery, two pulmonary veins, and a bronchus, covered 
by the pleura, where the latter extends from the lung to the pericar- 
dium. The relative situation is such, that the pulmonary artery is 
above, the bronchus in the centre and behind, and the pulmonary 
veins below. 

The texture of the lung is so light and spongy after an animal has 
once breathed, that its weight is very inconsiderable when compared 
with its volume. Its cells are left much distended, even when the 
animal is dead ; and, notwithstanding from its unusual elasticity, it 
expels a great quantity of "air when the thorax is opened, and is 
thereby reduced to a third of its size during life; yet it retains 
enough air to make it float in water, or even in spirits of wine. 
The quantity of air which the lungs contain differs very considerably 
in different individuals, depending entirely upon the capaciousness of 
the thorax. Its medium amount is computed at one hundred and 
forty-five cubic inches, thirty cubic inches of which are changed at 
every act of respiration. 



Of the Pleura * 

Each lung has a perfect covering of a serous membrane, called 
Pleura, to which it is indebted for its shining surface. This mem- 
brane is also reflected from the internal surface of the lung to the 
adjacent side of the pericardium, and is then spread over the inte- 
rior periphery of that half of the thorax to which it belongs, by 
lining the ribs and intercostal muscles, and covering the convex 
face of the diaphragm. There are, therefore, two pleurae, each of 
which is confined to its appropriate half of the thorax, so as to line 
its cavity and to cover its lung. 

The pleura, as other serous membranes, is a thin sac. Its circum- 
ference is entire, like that of an inflated bladder; there is, therefore, 
no point or line at which one may exclusively begin an account of 

* Anat. Atlas, Fig. 436. 



176 ORGANS OF RESPIRATION. 

its course and attachments. To commence, however, at the ster- 
num ; the pleura goes thence outwardly to line the lateral parietes 
of the thorax, as formed by the cartilages of the ribs, the ribs them- 
selves, and the intercostal muscles. In this way it may be traced 
around to the dorsal vertebrae, and over the convex surface of the 
diaphragm. In proceeding along the first rib, which is very oblique, 
it forms a sort of bulging bag, which projects towards the trachea, 
lines the lower part of the scalenus anticus muscle, and receives the 
upper extremity of the lung. The pleura, having reached the dorsal 
vertebrae from the ribs, passes from their sides forwards to the pos- 
terior part of the pericardium, a very small portion of which it 
covers. It then goes upon the posterior face of the pulmonary ves- 
sels and of the bronchus to the lung, and applies itself closely to the 
latter. It then covers the part of the lung posterior to its root, and 
continues to advance along the rounded surface of the lung to its 
anterior margin : it then passes over the internal surface of the lung, 
which is anterior to its root. It afterwards covers the front of the 
pulmonary vessels and of the bronchus, and gets in a very short 
space to the pericardium. It then passes forwards on the side of 
the latter, and having got near its middle line, goes from it to the 
sternum, and reaches the line from which the description of its 
course commenced. 

There is no important difference between the two pleurae, either 
in their mode of reflection or in the organs, to which they are at- 
tached, so that the description of one will apply to the other. The 
portion of each pleura covering the lung is called Pleura Pulmonalis, 
and that portion which lines the thorax is the Pleura Costalis ; that 
covering the Diaphragm is the Pleura Diaphragmalis. A duplica- 
ture of the pleura commences at the inferior margin of the pulmo- 
nary veins, and, descending as far as the diaphragm, attaches the 
inferior portion of the posterior margin of each lung, to the side of 
the pericardium in front of the vertebrae. This duplicature is the 
Ligamentum Pulmonis. It is longer on the left lung than on the 
right, by reason of the greater vertical diameter of the former. 

From what has been said it will now be readily understood, that 
the whole cavity of the thorax is divided vertically into two halves, 
by that portion of the two pleurae which advances from the spine 
towards the sternum. This septum is called the Mediastinum, and 
the heart, enveloped by the pericardium, is placed in its centre, 
and separates the two pleurae widely apart. It has been found 



THE LUNGS. 177 

useful by anatomists, for descriptive purposes, to subdivide the me- 
diastinum into three portions or regions. One passing from the 
front of the pericardium to the posterior face of the middle line of 
the sternum, is the Anterior Mediastinum ; another, passing from the 
posterior face of the pericardium to the dorsal vertebras, is the 
Posterior Mediastinum ; and a third, which is within the circuit of 
the first ribs, is the Superior Mediastinum. This division, though 
evidently arbitrary, is indispensable to a correct account of the 
relative situation of very important organs placed between the two 
pleurae. 

1. The Anterior Mediastinum is less important than the other 
two ; the portions of the two pleuras of which it consists are almost 
in contact, and contain between them some loose cellular substance 
by which they adhere together, and by cutting through which, after 
a longitudinal section of the sternum, they are easily separated from 
one another. The upper part of this septum contains the remains 
of the thymus gland ; its lower part leaves the middle line of the 
sternum, and inclines to the left side ; and when the sternum, is 
narrow below, it is attached to the anterior ends of the cartilages of 
the lower true ribs of that side. 

2. The Posterior Mediastinum, where it leaves the vertebras to 
reach the pericardium, passes off from a line nearer the heads of the 
ribs on the left side, than on the right. The descending portion of 
the thoracic aorta is contained within this septum, on the left side of 
the dorsal vertebras. The oesophagus is in its middle in front of the 
vertebras above, but, in descending it crosses in front of the aorta, 
and inclines to the left side of the dorsal vertebras to reaeh the fora- 
men cesophageum of the diaphragm. The vena azygos occupies 
the right side of this mediastinum, and, after ascending, forms an 
arch over the root of the right lung, and terminates by joining the 
descending cava. The thoracic duct, after entering the thorax be- 
tween the crura of the diaphragm, ascends in front of the dorsal ver- 
tebras between the aorta and the vena azygos, and behind the oeso- 
phagus, till it reaches the third dorsal vertebra ; it then inclines to 
the left side, and mounting into the root of the neck near the ver- 
tebras, it, finally, makes an arch, which, by advancing forwards, ter- 
minates in the angle formed by the junction of the left internal jug.u- 

16* 



178 ORGANS OF RESPIRATION. 

lar and left subclavian vein. The par vagum nerve, of both sides, 
is also in the posterior mediastinum. 

3. The Superior Mediastinum is bounded in front by the upper 
part of the sternum, behind by the upper dorsal vertebra?, and later- 
ally by the first ribs. The cavity is conoidal, with the base upward, 
but is too peculiar to admit of a rigid comparison with any thing 
else. The pleurae are reflected downwards from the internal edge 
of the first ribs, not abruptly, but in a rounded bulging manner, re- 
ceiving there, as mentioned, the tip or apex of the lungs, and lining 
the inferior surface of the scalenus anticus muscle. In order to un- 
derstand well the position of the pleurae, it must be borne in mind 
that the upper rib is placed very obliquely downwards and forwards, 
at an angle of about forty-five degrees with the spine ; consequently, 
the pleura, on being reflected from its whole internal edge, is much 
higher at the head of the rib than it is at the anterior extremity of 
the same. This cavity is continuous, of course, with that of the 
anterior mediastinum in front, and also with that of the posterior 
mediastinum behind. 

The remains of the thymus gland are where this cavity joins the 
anterior mediastinum : a part of the gland is, indeed, in each of these 
cavities just below the transverse vein. In contact with the right 
pleura is the descending Vena Cava. The common trunk of the 
Left Subclavian, and Internal Jugular, called the Transverse Vein, 
or Vena Innominata, after crossing in an oblique descent behind the 
upper portion of the sternum, joins the descending cava an inch 
above the place where the latter penetrates into the pericardium. 
Behind the transverse vein are the top of the arch of the aorta, the 
arteria innominata, the left carotid, and the left subclavian. The 
trachea, with the oesophagus behind it, descends along the middle 
line in front of the spinal column. The arteria innominata crosses 
the front of the trachea from left to right in ascending ; it is in contact 
with the transverse vein, and more superficial than either of the other 
arteries. The phrenic nerve, passing at the internal edge of the 
scalenus anticus, between the subclavian artery and vein, descends 
vertically in contact with the pleura. The par vagum passes along 
the side of the trachea, and afterwards behind the corresponding 
bronchus, having got into the superior mediastinum between the 
subclavian vein and artery : its inferior laryngeal branch encircles the 



THE LUNGS. 179 

subclavian artery on the right side, and the arch of the aorta on the 
left. 

The internal surface of the pleura is smooth and polished, and is 
moistened and kept lubricated by an unctuous serum, the natural 
quantity of which is merely sufficient to allow the parts to slide freely 
upon each other. In dropsy of the chest, it is augmented frequently 
to such an amount as to cause the collapse of the lung by pressing 
upon it. 

In the cellular tissue, between the pleura and pericardium, as well 
as on the diaphragm, adipose matter, in considerable abundance, is 
found in corpulent persons advanced in age. 

The blood vessels of the pleura costalis are derived from those 
which supply the parietes of the thorax, as the intercostals and 
phrenics. They ramify in the subjacent cellular substance, and end 
by exhalant orifices on the internal face of the pleura, from which a 
minute injection is poured out very copiously. 



BOOK VIII. 



OF THE CIRCULATORY SYSTEM. 

PART I. 

HISTOLOGY OF THE CIRCULATORY SYSTEM. 
CHAPTER I. 

General Considerations. 

The Circulatory or the Vascular System, consists in a congeries 
of tubes, or cylindrical canals, which convey the blood to and from 
every part of an animal body, and therefore, enter into the texture 
or composition of almost every portion of it. In all animals there 
seems to be a necessity for the alternate reception and discharge of 
alimentary materials; in the higher orders, this is effected through 
the agency of the vascular system ; but in the most simple animals 
this system does not exist, and their whole fabric being soft and 
permeable, nutritious matter is introduced by a direct absorption, or 
a species of capillary attraction, after the manner of a sponge, or 
any other porous body, and is discharged by a process equally 
simple.* It is probable that there are some parts of the human 
body whose mode of nutrition is analogous to the latter; as, for ex- 
ample, the articular cartilages, the hair, nails, and so on; for many 
observations tend to prove that all these organs have an interstitial 
circulation. 

* Hunter on the Blood. Beclard, Anat. Gen. 



182 CIRCULATORY SYSTEM. 

In many animals, the blood is propelled from a central point, 
called the heart, to all parts of the body, and then returns again to 
the heart. The first movement is executed through canals called 
arteries, and the second through veins. It is the most simple 
scheme by which a circulation can be carried on through a sangui- 
ferous system, and requires a heart with only two cavities; one for 
propelling blood into the arteries, or departing tubes, and another 
as a reservoir for receiving the blood of the returning tubes, or the 
veins. The two cavities must be near each other, and have a 
valvular opening between them, which will permit the blood to 
pass from the venous into the arterial reservoir; but not from the 
arterial into the venous. A circulation of this simple cast is found 
in fishes, and in animals generally whose respiration is effected on 
the surface of the body; but in man, and in other warm-blooded 
animals, where respiration is carried on interiorly by means of the 
lungs, their circulatory apparatus is double ; one part being for the 
lungs, and the other part for the body generally. 

In man, the heart consists of four cavities; two auricles, or re- 
servoirs of blood from the veins, and two ventricles, into which the 
venous blood is transmitted, and which, in their functions, may be 
compared to the forcing-pump of a fire-engine. The circulation is 
effected in the following manner: The blood contained in the right 
auricle of the heart flows into the right ventricle, and from the latter 
it is forced through the pulmonary artery into the lungs. It returns 
from the lungs through the four pulmonary veins, and is received 
into the left auricle of the heart; from the latter it flows into the left 
ventricle, and is propelled from it into the aorta. The aorta then 
distributes it through the whole body by an infinitude of small 
branches; from the latter it is collected, by corresponding veins, 
into two trunks, the Ascending and the Descending Vena Cava. 
The ascending vena cava brings the blood from the lower extremities 
and from the abdomen ; the descending vena cava brings the blood 
from the head and neck, the upper extremities, and the parietes of 
the thorax. These two trunks finally discharge the blood into the 
cavity from which it started, to wit, the right auricle. The same 
round is then renewed, and continues to be repeated during the 
whole course of life. It is customary for anatomists to call the 
route of blood from the right ventricle, through the lungs, to the 
left auricle inclusively the lesser or the pulmonary circulation ; and 



GENERAL CONSIDERATIONS. 183 

that which begins at the left ventricle, goes through the whole body, 
and ends in the right auricle, the greater circulation. 

The blood contained in the veins of the greater circulation, in 
the right auricle and ventricle, and in the pulmonary artery, is of 
a dark brown or reddish colour; while that contained in the pul- 
monary veins, in the left auricle and ventricle, and in the aorta and 
its ramifications, is from being vivified by respiration, of a carmine 
or vermillion complexion. The celebrated Bichat has, upon this 
difference of colour, founded his division of the whole circulating 
system into two parts; one containing black blood, " Systeme vas- 
culare a sang noire ;" the other red blood, "Systeme vasculaire a 
sang rouge." This division having general physiology for its object, 
affords a well marked distinction, suited to such discussions. 

The lymphatics also are a part of the circulatory system, but as 
they do not commonly convey red blood, the consideration of 
them will be introduced subsequently. " They take a very active 
part in the animal economy, whether natural or diseased, and seem, 
in many actions, to be the antagonists of the arteries, while the veins 
are much more passive being principally employed in returning the 
blood to the heart."* 

The largest vascular trunks are situated near the centre of the 
body and limbs, on the side upon which flexion is accomplished, 
while those near the surface are generally small. Most commonly 
there are one artery, one or two veins, and several lymphatics, all 
together. 

The arterial system in its external configuration may be com- 
pared to a tree, the trunk of which is attached to the heart, and 
which by a continued succession of divisions and subdivisions 
reaches to every part of the body. There are no means of estima- 
ting rigidly the collective area of the branches in proportion to that 
of the trunk, but a little observation on the size of the primitive 
branches will satisfy one of a great excess on the part of the latter ; 
and as the rule is maintained throughout, there must finally be an 
immense disproportion. We have then reason to believe, that if all 
the branches were assembled into a single cavity this cavity would 
be somewhat like a cone, the apex of. which would be next to the 
heart. The same rule holds in regard to the venous system, it being 
observed, however, that the latter has two trunks connected with the 

* Hunter, loc. cit. 



184 CIRCULATORY SYSTEM. 

heart instead of one. The general rule is, therefore, established 
throughout the vascular system, that the collective area of the 
branches is always greater than that of the trunk from which they 
proceed.* By the same rule the circulation in the branch must be 

* I am indebted to a scientific friend, Mr. Erskine Hazard, for the follow- 
ing computation, by actual measurement, of the arteries, from which it appears 
that in many of them, at least, the area of the trunks is greater than that of the 
branches near them. 

The Left Carotid at the Aorta is - - - - .42 

Its diameter at the branching is .43 

Increase of diameter .01 

Its square at the Aorta is 1764 

Each Carotid branch measures .28 and the sum of their squares is 1568 

The difference of the areas of the Carotid and its branches is 12J per cent, 
in favour of the Carotid. 

Diameter of Aorta near the Iliacs .... .64 

Its square ------ 4096 

Diameter of Left Iliac ----- .40 

Its square ----- 1600 

Diameter of Right Iliac - .37 

Its square ----- 1369 

Sum of their squares - 2969 

Aorta largest by nearly 38 per cent., or ... H27 

Square of Right Common Iliac, as above, ... 1369 

Ditto External Iliac ----- 900 

Ditto Internal do - .... 729 

1629 

Branches largest by nearly 19 per cent., or - - - 260 

Square of Left Iliac as above, - 1600 

Ditto Internal Iliac ------ 961 

Ditto External do ----- - 900 

1861 

Branches largest by above 16 per cent., or - - - 261 



GENERAL CONSIDERATIONS. 



185 



more languid than in the parent trunks, as this circulation is retarded 
both by additional friction and by having to fill up a larger canal.* 



Great Sinus of Valsalva 
Innominate 
Carotid - 
Subclavian 
Aorta beyond 

Sinus greater than all, by 
or 55 per cent. 



13456 



- 2601 

- 1444 

- 1024 

- 3600 



8669 

4787 



Comparison of the areas of the Iliac Arteries, with that of the Aorta, half an 
inch above them, in decimals of an inch. 



Greatest diameters - 
Least do 


- 


Left Iliac. 
.354 
.290 


Aorta. 
.556 
.410 


Right Iliac 
.390 
.290 


Sum of diameters 


. 




.644 


.966 


.680 


Mean diameters 


_ 




.322 


.483 


.340. 


Their squares 


103684 

he Iliacs 

of the Aorta - 


233289 


115600 
103684 


Sum of the squares of t 
Square 


219284 
233289 



Aorta larger than the Iliacs 
or nearly 6 fo per cent. 



14005 



As the areas of circles are to each other as the squares of their diameters, it 
follows that the aorta will contain, in a given length, nearly 6j 4 j per cent., 
more than the two iliacs; and, consequently, the blood must flow that much 
faster through the iliacs than through the aorta, as the same blood has to be 
disposed of in both, in the same time. By this means the power of the heart is 
continued much farther through the system, as each artery is large enough to 
supply its branches with but little friction. The interior surfaces of the above 
iliacs are, together, 2.0806 inches, while that of the aorta is but 1.518 inches, 
or only three-fourths of the rubbing surface. Independently of this circum- 
stance, it is found that there is a greater difference in the quantities of fluids 
passing through apertures of different sizes than there is in the areas of the 
respective apertures. This is accounted for by their being less friction between 
the particles of fluids, than there is between these particles and a solid ; and, 
in the larger apertures, a smaller proportion of the particles comes in contact 
with the solid. 

* It is computed that the blood moves 5233 times slower in the capillaries 
than in the aorta. 

Vol. II.— 17 



186 CIRCULATORY SYSTEM. 

The course of rivers exemplifies this continually ; while confined to 
narrow channels, they rush tumultuously through them, but when 
they begin to expand themselves into capacious basins, or to be di- 
vided into a multitude of smaller channels, the current becomes 
slower, and in some cases imperceptible, though the fact is clear, 
that an equal volume of water is every where descending in the 
same period of time. 

The moisture conferred upon all parts by the circulation of the 
blood, bears a sufficient analogy to the effects of irrigation upon 
ground. The water may be conducted to the latter by a canal, 
and is finally divided into an infinitude of streamlets, which ramify 
every where, and from the porosity of their beds percolate laterally, 
so that the whole field, even to its most minute atom, is kept moist- 
ened. The streamlets, afterwards, successively assemble again into 
a single canal, which bears off their superabundant water. From 
the nature of the particles of blood, many of them are confined to 
their proper channels, and can never pass off by percolation into the 
tissue, through which the blood vessels ramify. This may be 
proved by the fact of the red globules of blood having a diameter 
of from the three- thousandth to the five-thousandth part of an inch, 
a size inconsiderable as it is, yet too large to permit their flowing 
through elementary fibres or atoms ; whereas serum, or the water of 
the blood, may, from the extreme fineness of the particles, be ab- 
sorbed by any tissue whatever ; a circumstance entirely unquestion- 
able, both from daily observation, as, for example, in soaking a 
piece of dried meat or a bone ; and from the reflection, that the air 
itself will hold a certain quantity of water in solution. 

A question then arises whether the moisture of parts not supplied 
with red globules of blood, comes in the living body exclusively 
from infiltration or from a peculiar set of vessels called exhalants, 
often talked of, but as yet never seen ? That the lateral porosities 
of blood vessels are large enough to allow watery fluids to exude, 
is readily proved by injecting water into the blood vessels of a 
limb, or, of any other part, when the latter invariably becomes cede- 
matous. It is in this way even possible to inundate a living animal, 
as I have seen accomplished by M. Magendie, in Paris. This 
moisture requires a change, and by continued additions would be- 
come superabundant : as it has been thrown out of the common cur- 
rent of the circulation and could not be removed in any other way, 
the lymphatic system has, therefore, been added for the purpose. 



GENERAL CONSIDERATIONS. 187 

In the lower orders of animals, who are destitute of the blood ves- 
sels, the interstitial change of moisture goes on without lymphatics. 

No part of the human body is exempt from moisture, but it is 
furnished by smaller streams, and is also less abundant in some tex- 
tures than in others ; for example, though blood vessels susceptible 
of conveying red blood do ramify through tendons and ligaments, 
yet they are not numerous, apparently ; not more so, indeed, than 
what is- sufficient to keep up by a deposite of serum, the flexibility 
of those parts. The vascularity of a part during life may be ascer- 
tained by a simple process after death, the most vascular always lose 
proportionately of their bulk by drying ; for example, a muscle shrinks 
more than a tendon, a gland more than a muscle. 

Besides the operation of the lymphatics, much of the super-abun- 
dant moisture is carried off by insensible perspiration and evapora- 
tion from the surface of the body : the latter process, however, is 
much restrained by the peculiar character of the cuticle, without 
which it would become excessive, probably so much so as to exceed 
any supply of fluid through the stomach. 

The red globules of the blood, besides their less obvious uses, 
unquestionably serve to inspissate the serous or watery part, by an 
intimate mixture with it, and thereby put a certain restraint upon its 
extravasation. They also, from their size, serve to keep open the 
channels through which the blood circulates. So much associated 
is the existence of red globules with regular blood vessels, that there 
are but few examples of animals having the former, without also 
having the latter ; whereas, in animals whose circulating fluid has 
not red globules, but is a mere serum, the entire destitution of regular 
blood vessels is very common, and their circulation, if the name be 
deserved, consists simply in the transmission of moisture from one 
pore to another, as occurs in a rag or in a sponge, by mere capillary 
attraction. Such animals form a numerous class in the chain of 01% 
ganized beings, and have a gelatinous consistence. 

A remarkable feature in the vascular system, both arteries and 
veins, is the disposition of trunks to run into one another ; or to form 
an anastomosis, whereby, if the blood should be cut off by one route, 
it may still be supplied through another. These communications 
are frequent in the head, in the neck, in the thorax, in the abdomen, 



188 CIRCULATORY SYSTEM. 

and in the extremities; they exist, indeed, wherever the blood ves- 
sels do, and become more numerous as the blood vessels are smaller, 
or more removed from the centre of the circulation. It is unneces- 
sary here to specify instances, as the more remarkable ones will be 
mentioned at a proper time. But some estimate may be made of 
their importance, and of the facility of communication established 
by them, when it is remembered that cases have occurred of ob- 
structed aorta, without the circulation ceasing in the parts of the 
body beyond it : the same has occurred to the venae cavse, and to 
the thoracic duct also.* 

The extreme vascular ramifications are called Capillaries, ( Vasa\ 
Capillaria,) and they form the connexion between the arteries and 
veins; or, by being intermediate to the two, they are the ultimate 
terminations of the arteries, and the commencing roots of the veins. 
From the extreme tenuity of these vessels, it is impossible to indi- 
cate where the arteries terminate and the veins begin ; yet their con- 
tinuity with the capillary system has been repeatedly demonstrated, 
by throwing injections from the one into the other system ; and by 
microscopical observations made on the transparent parts of living ani- 
mals, as the mesentery and the web foot of frogs, and the tail of fishes. 
These facts are sufficiently substantiated by the observations of Mal- 
pighi, Leeuwenhoeck, Prochaska, and a crowd of others; yet there 
are anatomists who hold a contrary doctrine, and admit the paren- 
chyma of the ancients (an indefinable something, conceived, how- 
ever, to be spongy) as a point of termination for the arteries, and of 
commencement for the veins. 

Though the capillaries are all too fine to be seen distinctly without 
the microscope, yet they are found to have several gradations of size. 
The largest of them are those which only escape the naked eye, ex- 
periencing successive divisions, whereby their diameters are reduced 
from admitting a file of several globules of blood to the caliber of one 
globule only .| The capillaries have also frequent anastomoses with 
one another. Sometimes the artery is simply doubled on itself, and 
immediately becomes a vein : on other occasions, several capillary 
arteries run into the same vein. 

The anastomoses finally end in a continuous intertexture of ves- 

* Beclard, Anat. Gen . 

f Anat, Atlas, Figs. 431, 432, 433. 

% Beclard, loc. cit. 



CAPILLARIES. 189 

sels, which is common to the arteries and veins both. Although the 
limits of the two sets of vessels, can not be precisely denned, so as 
to learn where one set ends, and the other set begins, yet the capil- 
lary system may be known by the greater uniformity of size in its 
vessels. 

Their diameter varies from the j±^ to the — 1 — of an inch, but 
the medium measurement is from the tsVo to 3 ,Vff of an inch. The 
following table will show the result of measurements upon injected 
preparations : 



Brain . 


_ j 

4-70U 


' according 


to Weber, 


Kidney 


TJ25 tO j-Sffff 


it 


Muller. 


Ciliary processes 


vhx 


a 


a 


Mucous Membrane ~) 


i 






of Large intestine $ 


• Tsir to 2i5? 


a 


Weber. 


Lymphatic Gland 


T8?i to jVss 


a 


a 


Skin . 


T145 


a 


a 


Inflamed Membrane 


ivVg to saVs 


a 


a 



As a general rule their diameter may be stated at from one to five-' 
globules of red blood.* 

By the above, it will be seen that their diameter is sufficiently 
large for transmitting the blood discs. But the capillaries are de- 
cidedly smaller than any of the tubular structures of the body. 

The capillaries pass between the primitive fibrils of muscles and 
nerves, and form an intertexture around them, but as in other tissues 
of a very fine kind, they do not penetrate them, because those tis- 
sues have in their elementary filaments a finer diameter, than either 
the capillaries, or even the red globules of the blood. 

When the capillary communications are unduly enlarged, they 
constitute what has been called by Mr. John Bell the aneurism from 
anastomosis, a frequent mark in young children, and which, when 
it has developed itself fully, has a spongy structure resembling the 
erectile tissues, as the corpus cavernosum penis, &c. As there is 
a double circulation, so there is a double capillary system, one for 
the lungs and the other for the body generally : to these may be 
added a third, which exists in the liver between the hepatic extremi- 
the venaportarum and the hepatic veins. 

The texture of the capillary vessels is too fine to admit of much, 

* Beclard, loc. cit. 
17* 



190 CIRCULATORY SYSTEM. 

scrutiny, but they appear as simple cylindrical excavations in the 
substance of the part to which they belong. This appearance has 
led many respectable anatomists to the conclusion, that they were 
absolutely destitute of walls. Gruithuisen saw the blood flowing in 
free spaces between the" acini of the liver in the frog. Muller saw 
the same, in the liver of the larva of the triton. Wedmeyer came to 
the same conclusion, in witnessing the broad currents of blood with 
the small islets, between them in the lungs of the salamander. There 
are many other authorities on the same side. On the contrary, Leeu- 
wenhoeck, Haller, Spallanzani, Prochaska, Bichat, Berres and Ru- 
dolphi, admit the existence of such membranous walls. Without 
the latter, we can scarcely account for the anatomical injection of 
fluids, passing from the arteries into the veins, without extravasation; 
and for currents of blood, crossing above and below each other, 
without mixing. Windischman has injected in the cochlea of birds, 
the blood vessels of a very soft plicated membrane, which, upon being 
dissolved in water, left a beautiful vascular net work with the meshes 
empty. Schwann has observed in the capillaries of the mesentery of 
the frog, an arrangement of circular fibres, and Muller after injecting 
the vessels of the kidney of a squirrel and macerating the glandular 
structure off, found the capillaries on the tubuli uriniferi, apparently 
independent vessels.* 

It is not improbable, that they may be uninterrupted continuations 
of the internal coat of the arteries into that of the veins. They have 
• striking powers of extension and of contraction, and are easily irri- 
tated. An emotion of the mind, as a sentiment of shame or a feel- 
ing of resentment, quickly causes those of the face to become turgid 
with blood. Local stimuli cause congestions in them. Cold, the 
application of a weak acid, or fear, causes them to contract ; though, 
under the influence of the heart, they are less so than larger vessels. 
Their innumerable channels cause a comparatively languid circula- 
tion of the blood in them, for reasons mentioned ; and by furnishing 
it with more places of contact with their parietes, put it more under 
nervous influence than it is elsewhere. 

These vessels are not equally abundant in all the textures of the 
body. Their quantity may be ascertained by the redness which a 
part acquires by inflammation, as well as by fine injections: the 
latter proof is preferable, as, in the former, it is difficult to distin- 

* Muller, Phys. p. 230. 



CAPILLARIES. 191 

guish them from the extravasations which also occur at the same 
time. The celebrated injections of Ruysch, from their unusual 
minuteness, induced him to think that every solid portion of the 
body was vascular, yet he admitted that some portions were more 
vascular than others, thereby conceding to his antagonists, that some 
points at least were not formed by bloodvessels. In the microsco- 
pical examinations of living animals, for example the frog, it is seen 
that in their feet the smallest capillaries are separated by distinct 
intervals, while in the mucous membrane of the lungs the finest 
needle cannot have its point inserted without opening several of 
them.* The younger an animal is, the more vascular are its parts: 
but, on the contrary, as it advances in age, the proportion of parts 
not susceptible of injection increases, while the capillaries diminish 
in number. In cold-blooded animals, it is very evident that some 
of these capillaries, or arterio-venous communications, are large 
enough to admit a file of several red globules abreast, while others 
allow a single file only. 

The arrangement of the capillary net-work is for the most part 
uniform, the principal variation being in the size of the meshes, and 
in their being elongated or not. In muscles and nerves, the elon- 
gation is in the direction of the primitive fibrils, and the same may 
be said of every tissue consisting of parallel filaments. In the in- 
testines, the capillary vessels being first arborescent, they anastomose 
very freely; in the placenta they resemble a tuft, in the spleen a 
sprinkling brush, in the tongue a hair pencil, in the liver a star, in 
the testicle and choroid plexus of the brain a lock of hair, in the 
Schneiderian membrane a fine trellis work. In the cortical portion 
of the kidney, there are glomeruli or small bulbs of vessels in the 
midst of the common anastomosis and fine vascular net-work ; 
having wound itself up in that way, the artery then emerges on the 
other side, and is lost in the adjacent capillary tissue. This is 
said according to Teidemann to be particularly distinct in the triton 
and salamander. At the extremity of the villus of the human pla- 
centa a minute artery is directly continuous, with a minute returning 
vein. 

In the medullary portion of the kidneys, in company with the 
ducts of Bellini, the arteries and veins, run parallel with these ducts 

* Beclard, Anat. Gen. 



192 



CIRCULATORY SYSTEM. 



anastomose across them forming elongated meshes, and finally ap- 
pearing on the papillae renculi, terminate in a fine net-work, sur- 
rounding the orifices of the uriniferous ducts. This vascular ar- 
rangement is frequently mistaken for the tubuli urinifeii themselves. 



Fig. 32. 



Fin-. 33. 




Distribution of Capillaries 
in the Villi of an Intestine. 




Distribution of Capillaries 
around the follicles of a Mucous 
Membrane. 



The most attenuated capillary net-work exists in the lungs, and 
in the choroid membrane of the eye. The interspaces are some- 
what larger in the iris and ciliary body. The mucous membrane 
of the intestines, especially of the veins, has its capillary net-work 
so fine as to form almost the entire structure apparently, when it 
is successfully injected. Bones, ossific cartilages, tendons, liga- 
ments, and the fibrous structures, generally are furnished with the 
fewest of them, and have the largest meshes. 



Fig 34. 



Fig. 35. 




Distribution of Capillaries 
around the follicles of the Parotid 
Gland. 




Capillary Network of the 
Nervous Centres. 



The nutrition of the body depends upon an alteration of exhala- 
tion and of absorption; but it is still undetermined, whether there 
be any vessels whatever whose especial office is that of exhalation, 
and which produce the several secretions and exhalations. If there 
be such, they are generally designated by the term exhalants, and 
their diameteis are too small to transmit the red globules of blood ; 



EXHALANTS. 



193 



their function is, consequently, to give passage to the serous particles 
only. 

Fig. 36. Fiff. 37. 





Capillary Network in 
the mucous membrane of the 
palpebral conjunctiva. 



Capillary Network in the 
choroid coat of the eye. 



This subject has been much agitated by anatomists, and marshals 
the best authorities on both sides. Among the distinguished advo- 
cates in the affirmative, are Boerhaave, Haller and Bichat ; and op- 
posed to them, are Prochaska, Mascagni, and Richerand. The 
leading facts of the former are ; The microscopical observations of 
Leeuwenhoeck, who speaks of vessels admitting only serous globules ; 
the phenomena of inflammation, which render red, parts naturally 
white and transparent : the difficulty of conceiving how the nourish- 
ment of certain parts can be maintained, whose capillary system of 
red blood is so limited, in proportion to points not susceptible of it. 
The opinion of Mascagni and others to the contrary, is : That those 
exhalants, if they existed, should be seen readily, inasmuch as they 
are within the range of a microscope, whose powers enable one to 
examine a body much smaller than a red globule of blood ; that in- 
jections should penetrate them, instead of being limited to vessels 
whose existence is sufficiently confirmed by examination in the 
living state ; that if during inflammation they do seem to be injected 
with red blood, the appearance is delusive, and depends upon the 
existing capillaries being dilated so as to receive more red blood 
than usual, upon the formation of new vessels, and upon sangui- 
neous infiltration ; and as to membranes naturally white, as the con- 
junctiva, the colour depends upon the capillaries, while in a healthy 
state, being so small that they do not admit the red globules in a 
file sufficiently numerous to be perceived by the eye ; the globules 



194 CIRCULATORY SYSTEM. 

being, probably, then conducted in a series of one only, or in a 
single file, like a string of beads. It is, therefore, much more rea- 
sonable not to admit the existence of vessels which it is very doubt- 
ful whether any one has seen, unless we claim as such the vessels 
which, under ordinary circumstances, do not convey red blood, 
at least in a visible manner ; but are limited to the carrying of the 
liquor sanguinis, or, in other words, pure serous vessels, the exist- 
ence of which is affirmed by Miiller. 

When a watery injection is pushed into a blood vessel, it in a 
little time shows itself as a fine dew upon the surface of the serous 
and mucous membranes ; in the cellular membrane, and elsewhere. 
According to many anatomists, it has gone through the system of 
exhalants, and, indeed, presents itself to sight in very much the same 
way that exhalation occurs in the living state. From the view which 
has just been taken, it becomes more probable, that this perspira- 
tion is executed through the interstices or pores of the vessels. In 
the dead state it is merely a mechanical result, a simple straining of 
the fluid; whereas, in the living body it is a vital function, continu- 
ally modified by the peculiar vital powers of the organ or membrane 
where it occurs ; and, therefore, presents itself under the form of the 
different secretions. The question of the exhalants being a distinct 
set of vessels, does not, however, appear to be one of much conse- 
quence ; because, if they do exist, they must be very short and verv 
small : and the assumption of their existence does not throw an) 
light upon the function of secretion. For the latter is still an incom- 
prehensible vital process, and as far as we have any idea about it. 
it is quite as easy to conceive of its being performed in the parietes 
of the capillaries, as in the mouths of a distinct set of vessels, whose 
length is too short to admit of an estimate. 

Besides the supposed existence of a general system of exhalant 
vessels, some anatomists have thought that there was a species of 
them acting particularly as nutritive vessels. According to Boer- 
haave, every part must, therefore, be vascular. Mascagni thought 
that the extreme arterial ramifications are not only famished with 
exhaling, but also with nutritive porosities ; and that there are every 
where orifices of absorbing vessels, to contain the nutritive mole- 
cules. The theories of Bichat and of Prochaska, do not differ ma- 
terially from the latter. Whatever may be the mode of existence, 
and the route of nutriment to the several parts of the body, the opera- 
tions involved are entirely too subtle even for microscopic observa- 



TEXTURE OF THE ARTERIES. 195 

tion. We, therefore, can only understand, in a general way, that 
the blood vessels deposite, and the lymphatics absorb, by invisible 
avenues in the cellular substance, the molecules of composition and 
of decomposition in our organs.* It is to this power that the name 
of vital force has been given, and especially that of the force of for- 
mation, (nisus formativus.) 

The arteries, though commonly said to be cylindrical canals, are 
not exactly so, but, as they recede from the heart, increase somewhat 
in diameter, even where they do not send off any branches. In this 
way the arteries of the umbilical chord are evidently larger as they 
get nearer the placenta ; and the spermatic arteries of a bull as they 
get nearer to the testicle. Observations made on the carotid arteries 
of the camel, and of the swan, by Mr. Hunter,f tend to prove the 
same disposition in them. The vertebral arteries afford a striking 
example of the same. It is probable that the rule extends to all 
arteries throughout the system, but it cannot be ascertained with so 
much certainty, because of the close succession of branches which 
they send off. 

Arteries have within themselves a power of increase connected 
with the exigencies of the part to which they go ; thus, the uterine 
arteries increase much in their capacity during pregnancy, while the 
hypogastric, from which they are derived, augment inconsiderably, 
and the primitive iliacs not in an appreciable manner. In animals 
of the deer kind, whose horns are deciduous, the same augmentation 
of arterial trunks occurs while the horn is growing. Tumours are 
supplied in the same way. But in all these cases, after the exigency 
is passed, the vessels diminish to their primitive size. 

With the exception of the semi-lunar valves at the orifice of the 
pulmonary artery and of the aorta, there are no others in the whole 
arterial system. These valves permit the blood to pass in the direc- 
tion of the circulation, but not backwards, as they are closed imme- 
diately upon the cessation of the contraction of the ventricles. The 
tricuspid valve of the heart, and the semi-lunars of the pulmonary 
artery, are naturally not so perfect in their closure as those on the 
other side of the heart, but permit a small quantity of blood to retro- 
grade.! As life advances, the valves of the aorta are much disposed 
to ossification and derangements of different kinds, which render 
them much less perfect than those of the pulmonary artery. 

* Beclard, loc. cit. 

f On the Blood and Inflammation. \ Hunter, loc. cit. 



196 CIRCULATORY SYSTEM. 

CHAPTER II. 

Of the Textnre of the Arteries. 

The arteries are composed of three coats , an external, a middle, 
and an internal. 

The External Coat, also called Cellular, is, in fact, condensed 
cellular substance formed into a cylinder. Its fibres run in every 
direction, so as to be perfectly interwoven with one another. The 
exterior periphery of this coat is continued into the adjacent cellular 
substance, but its internal face is united more closely to the middle 
coat ; not, however, so tightly as to prevent a slight sliding of the 
one upon the other, and to forbid their easy separation by a knife. 
Scarpa is not disposed to admit this as one of the coats of arteries, 
and says that it only serves as an exterior envelope, and retains them 
in their places. This coat manifests its fibrous character in not being 
disposed to secrete fat, and is more distinct in the large arterial trunks. 
It has considerable strength and elasticity, both circularly and longi- 
tudinally, and is remarkable for its whiteness. If an artery be sur- 
rounded by a tightly drawn ligature, the middle and the internal 
coats will be completely cut through by it, while the external coat 
remains entire. This coat, then, answers the purpose of a strong 
investing fascia,* in which respect it may be considered as a sheath 
to the proper arterial structure, though the term sheath is commonly 
applied to the cellular membrane on its outer side. 

The Middle Coat of the arteries is called the Muscular, the Proper, 
the Tendinous, and so on. It is of a light yellowish tinge, and de- 
creases continually in thickness, with but few exceptions, from the 
heart to the ends of the arteries; it is, how T ever, proportionately 
thicker in the small arteries than in the large ones. Its fibres are 
circular, but do not individually perform the circuit of the vessel. 
They are parallel to each other, and adhere laterally by very slender 
ties. In the larger arteries, this coat may be divided into several 
laminae, though the division is entirely artificial. There are no lon- 

* Jones on Hemorrhage. 



TEXTURE OF ARTERIES. 197 

gitudinal fibres whatever in it ; the consequence of which is, that an 
artery divested of its external coat, yields more readily in the direc- 
tion of its length than of its circumference. 

The middle coat has a firmness, whereby, even when an artery is 
emptied, the cylindrical shape is still retained. Its character seems 
to be the result of a mixture of elastic and of muscular properties 
derived from a state of tissue entirely peculiar; but which some ana- 
tomists have been very desirous of ranging under the head of mus- 
cles, others under that of ligaments, and a third, under both united. 
The celebrated John Hunter, whose observations were generally 
made with the most scrupulous attention to perfect exactitude ; were 
often repeated, so as to make one confirm another; and who has 
received that sanction of greatness in which one's posthumous repu- 
tation becomes more exalted than the living ; bestowed much atten- 
tion on this subject. He was induced to believe that this middle 
coat was formed by a muscular lamina internally, and an elastic one 
externally ; which distinction might be rendered evident by cutting 
a contracted artery through transversely, when the muscular coat 
would be found projecting beyond the other. He acknowledges, 
however, that he never could discover the direction of the muscular 
fibres ; though he supposed them to be oblique, because their degree 
of contraction was greater than a straight muscle could produce. 

The elastic contraction of an artery, is manifested both in the di- 
rection of its length and of its circumference ; for, when put upon the 
stretch in either way, it has the ability of returning to its original di- 
mensions after the distending force ceases. The muscular contrac- 
tion, however, only occurs in the circumference, and not at all in 
the length : by it the caliber of arteries is reduced to a very small 
diameter, if an animal be slowly bled to death. If, in this con- 
tracted condition, an artery be slit open longitudinally, the elastic 
coat will, at the cut margin, project beyond the other, which Mr. 
Hunter considers as another way of ascertaining the existence of the 
two tunics. But if this same artery be then stretched transversely, 
the muscular coat will project beyond the other ; for the reason, that 
if a muscle, after death, be elongated by force, it has no power of 
returning from that state, but will remain precisely as it is : whereas, 
elasticity being a property of matter enjoyed quite as fully in the 
dead as in the living state, the elastic coat of the artery returns to 
the medium condition. 

Mr. Hunter, with a view of satisfying himself on these several 
Vol. II.— 18 



198 CIRCULATORY SYSTEM. 

points, had a horse bled to death, so as to obtain the vessels, at their 
minimum of contraction. A circular section of the aorta measured, 
at first, five inches and a half, and, on being stretched, it lengthened 
to ten inches and a half; being let alone, it contracted to six inches, 
at which it remained stationary ; the difference between six inches 
and ten and a half, was then the amount of its elastic power, while 
only half an inch of contraction was due to the muscular stratum, or, 
in other words, an eleventh of the whole. 

A section of the iliac artery, measuring two inches in circumfe- 
rence, on being allowed to contract after stretching, measured two 
and one-third inches ; it, therefore, gained one-sixth the amount of 
its muscular contraction. A section of the axillary artery gained 
one-eighth — of the carotid, two-thirds — of the radial artery, doubled 
its primitive extent. From all which the inference was drawn, that 
the power of recovery in a vessel is greater, in proportion as it is 
nearer the heart, but lessens as the distance increases, which shows 
the decrease of elastic, and the increase of muscular power. 

The elastic coat gives a middle state to an artery, or has a con- 
tinued tendency to it ; if, therefore, the artery be too much dilated, 
it contracts it, and if it be too much contracted it dilates it, all of 
which is readily exemplified by a cylinder of gum elastic, which, 
whether compressed or dilated has only one state of repose, to which 
it immediately returns on being left to itself. Mr. Hunter supposed, 
that a certain degree of elasticity is continued to the very end of 
every artery, from this quality being better suited to sustain a per- 
manent resistance than muscular power ; as a pipe of lead, from its 
want of elasticity, finally becomes stretched and useless under the 
pressure of a column of water, whereas, one of iron, from being 
elastic, always reacts efficiently. It is this elasticity in the arteries, 
which causes the blood, at a little distance from the heart, to flow 
through them in a continued jetting stream when they are opened, 
although it is supplied to the aorta by interrupted strokes. In this 
way, as the artery is more distant from the heart, the stream becomes 
proportionately regular. 

" The muscular power of an artery renders a smaller force of the 
heart sufficient for the purposes of circulation; for the heart need 
only act with such force as to carry the blood through the larger 
arteries, and then the muscular power of the arteries takes it up, 
and, as it were, removes the load of blood while the heart is dilating. 
In confirmation of this remark, it is observable in animals whose 



TEXTURE OF THE ARTERIES. 199 

arteries are very muscular, that the heart is proportionably weaker, 
so that the muscular power of the vessels becomes a second part to 
the heart, acting where the power of the heart begins to fail, and 
increasing in strength as that decreases in power."* 

After many discussions on the above, the present state of micro- 
scopical anatomy may be considered as leading to the following con- 
clusions. The fibres which make the middle coat of the arteries are 
identical with those of the ligamenta flava of the vertebral column 
and the analogous tissue, as the elastic ligamentous structure of the 
trachea, and the vocal or crico-thyroid ligaments of the larynx. This 
elastic tissue is every where distinguished by the great inequality in 
the size of its fibres, and by their anastomosing with each other. It 
is of a yellow colour, and its elasticity is well, though not fully pre- 
served in alcohol for an indefinite duration. This elasticity is an 
almost purely physical quality, both in the living and dead state, not 
absolutely so, but a near approach to it. 

Among the traits which distinguish the middle coat of the arteries 
from muscular tissue, is, its not contracting under the strongest elec- 
tric and galvanic stimuli, like muscles commonly. Nysten repea- 
tedly experimented with galvanism on the aorta of criminals just 
beheaded, but did not perceive the slightest contraction of its fibres. 
Similar experiments with the same results have been instituted by 
many others, and amongst them Muller.f 

The fibres of the elastic tissue are prismatic, or four sided, and 
have a diameter from ^ ff0 to ^~ of an inch. In the coat of the 
arteries their course is more decidedly circular and parallel than in 
the ligaments. In both cases the heat of boiling water draws them 
up, but does not destroy their elasticity. 

The Internal Coat of the arteries is designated by the terms Ner- 
vous and Arachnoid. It is continued from the ventricles of the 
heart, in the left one of which it is of greater thickness. It is the 
duplication of this membrane with some fibres interposed, that com- 
poses the semi-lunar valves of the aorta and of the pulmonary artery. 
Its internal face is smooth, polished, and moistened with a kind of 
humidity which permits the blood to flow through with diminished 
friction. In the larger arterial trunks, some small longitudinal 
wrinkles are observable in it ; and when an artery has been cut 
through, as in amputation, it is disposed to retract in small trans- 

* Hunter, loc. cit. f Loc. cit., p. 217. 



200 CIRCULATORY SYSTEM. 

verse wrinkles. It is, therefore, not very extensible, but has, accord- 
ing to the experiments of Sir Everard Home,* a considerable degree 
of solidity and strength. 

The internal coat of arteries possesses, to a limited extent, the 
elastic and other qualities of the middle, bat it is generally considered 
as belonging to the class of serous membranes. A very delicate 
layer of epithelial scales with oval nuclei, according to Henle, occu- 
pies its internal face. This coat may be stripped with great facility 
from the aorta after steeping it for some time in alcohol. It is then 
found to be very thin and semitransparent. 

Ossifications of this membrane are very frequent after the age of 
sixty. 

In addition to the tunics mentioned, cellular substance, vessels, 
and nerves enter into the structure of arteries. 

The Cellular Substance is not abundant, and serves principally to 
unite the sides of the circular fibres to one another, and to join the 
internal to the middle coat. 

The Vessels (Vasa Arteriarum) consist both in arteries and in 
veins, and come from the adjacent trunks, instead of from those on 
which they ramify. They may be made very distinct by a fine in- 
jection, or by laying them bare in the living body ; when in a little 
time after exposure, they begin evidently to carry red blood, and to 
grow turgid as in inflammation. The difference in the colour of the 
blood distinguishes these arteries from the same kind of veins. Both 
arteries and veins may be traced very well into the middle coat, but 
not upon the internal, though the changes which occur in the latter, 
from disease and upon the application of ligatures, prove clearly 
that exhalation and absorption are continually going on there. For 
in inflamed arteries, an exhalation is seen upon their internal surface, 
and when a coagulum has been produced by ligature, it is finally 
absorbed. 

The Nerves of the arteries, according to Wrisberg and Beclard, 
are numerous and considerable, form around them a plexus resem- 
bling that of the par vagum around the oesophagus, and follow them 
into the interior of our organs, with the exception of the brain ; which 
has them only to its surface. They are proportionately more abun- 
dant in the aortic than in the pulmonary system ; also upon the smaller 

* Transactions for the Improvement of Medical and Surgical Knowledge, 
vol. i. 



TEXTURE OF THE ARTERIES. 201 

than upon the larger arteries. The arteries of the head, of the neck, 
of the thorax, and of the abdomen, are supplied from the sympa- 
thetic nerve, while those of the extremities are supplied from the 
nerves of the spinal marrow. 

The passing of the blood through the arteries is accompanied 
with a pulsating motion, which, for the most part, is exactly syn- 
chronous with the contraction of the left ventricle, and depends 
upon an increased quantity of blood thrown into them at the moment. 
The dilatation of the artery may be both seen and felt; "but were 
we to judge of the real increase of the artery by this, we should 
deceive ourselves; for when covered by integuments, the apparent 
effect is much greater than it really is in the artery itself; for in 
laying such an artery bare, the nearer we come to it, the less visible 
is its pulsation ; and, when laid entirely bare, its motion is hardly 
either to be seen or felt. This apparent diastole of the artery is 
augmented in proportion to the solid matter covering it, whence 
tumours over large arteries have considerable motion given to them, 
and have often been supposed to be aneurismal. Arteries, in fact, 
during their diastole or dilatation, increase much more in length 
than in width, and are thrown into a serpentine course: instead, 
therefore, of the term diastole, it should rather be called the elon- 
gated state."* Mr. Parry, of Bath,f has denied that the arteries 
dilate at all during their diastole: his opinion however, is peculiar, 
though, in an experiment performed many years ago upon the carotid 
artery of a calf, its correctness appeared to me then to be fully 
proved. 

There is no part of the human body which presents more fre- 
quent varieties, in different individuals, than the arteries. These 
varieties are found, in their place and manner of origin, in position,, 
and in the number of their ramifications. They are comparatively 
rare in the trunks of the first order, more common in those of the 
second, and still more usual in those of the third and fourth. From 
these causes, discrepancies are continually found in the descriptions 
of the most approved authorities, and must last so long as writers- 
repose upon a partial experience, instead of referring to what has 
been most generally observed. 

* J. Hunter, loc. cit. f Experimental Inquiry on the Pulse, 1816-1819'. 

18* 



202. CIRCULATORY SYSTEM. 



CHAPTER III. 

0f the Texture of the Veins. 

The veins, from their duly of receiving the blood in all parts of 
the body from the extreme arteries, and returning it to the heart, 
by successively collecting it into the two vense cavse, may be more 
appropriately compared to the roots of a tree, than to its branches. 
The variations in them, as well as their anastomoses, are more fre- 
quent than in the arteries. 

They are more numerous than the arteries; for, in addition to two 
venous trunks attending each artery wherever the structure of the 
part is intended for locomotion, as in the extremities, and in some 
places upon the trunk of the body, there is a very abundant class of 
veins which are superficial or subcutaneous, and which, when filled 
properly with injecting matter, form a fine vascular net-work over 
the whole surface of the body.* These superficial veins, in some 
places, form trunks even larger than such as attend the arteries, and 
especially in the extremities. Besides the excess in number, the 
veins which attend the arteries (Vence Comites) have a capacious- 
ness which, in many cases, is double that of the latter. From these 
several circumstances, it results that the area of the venous system 
vastly exceeds that of the arterial. 

In some cases the veins follow precisely the course of the arteries, 
one for one, as in the greater number of the viscera of the abdomen, 
where they have common points of entrance and departure. Some- 
times two arteries discharge into one vein, as in the penis, the 
clitoris, and the umbilical chord ; sometimes they pursue a course 
entirely different from the arteries, as in the pia mater. For the 
most part they are less tortuous than the arteries. 

The veins, when injected, assume a cylindrical shape, yet they 
differ materially from the arteries, in having much thinner coats, 
and in being so pliable that they collapse by their own weight. In 
the lower extremities, however, near the feet, and upon them ; as 
the veins sustain the pressure of a long column of blood, they have 

* Pauli Mascagni Ar.atom. Magna. Pisis, 1823. 



TEXTURE OF THE VEINS. 203 

additional thickness and strength, so as to approximate them more 
to the arterial structure. This provision will be found occurring in 
most places where they have much duty to perform. 

" They are similar to the arteries in their structure, being com- 
posed of an elastic and muscular substance ; the elasticity preserves 
them in some degree in a middle state, although not so perfectly as 
it does in the arteries. The muscular power adapts the veins to the 
various circumstances, w f hich require the area to be within the middle 
state, and assists the blood in its motion towards the heart."* 

The External Coat is thinner and not so strong as that of the 
arteries ; in other respects, the resemblance is sufficiently close not 
to require any particular comment. 

The Middle Coat, near the entrance of the larger veins into the 
heart, is distinctly muscular.f It is formed of soft extensible fibres, 
many of which, when the vein is held up to the light, appear longi- 
tudinal, while the most internal are circular: there are difficulties, 
however, in the separation of these fibres, which prevent their course 
from being accurately ascertained. Admitting this coat with the 
exception of its muscular ingredient near the heart, to be of the 
same tissue, that is the elastic ligamentous which prevails in the ar- 
teries, yet the filaments composing it are much more decidedly in- 
termixed, according to my personal observations. Bichat and 
Meckel assert, that the whole of them are longitudinal, and that 
there are none circular. 

This coat in the human subject, is much thicker in the system of 
the ascending than of the descending cava ; it is also thicker in the 
superficial than in the deep-seated veins. In some subjects it is 
much better developed than in others. In certain parts of the body 
it is entirely deficient, as in the sinuses of the dura mater, and has- 
its place supplied by this membrane ; the same deficiency exists in 
the sinuses of the bones. 

The Internal coat is more delicate and extensible than the corres- 
ponding one of the arteries, is less liable to rupture, and less disposed 
to ossification. It is thrown into a considerable number of duplica- 
tions, forming valves. Each valve is of a semicircular shape ; is con- 

* Hunter, loc. cit.. f Beclard, loc. cit. 



204 CIRCULATORY SYSTEM. 

nected by its curved edge to the vein, while the straight edge is loose, 
and turned towards the heart. When the veins are injected back- 
wards, these valves may be forced in the larger trunks, and give 
them a knotted appearance. The valves are commonly in pairs, 
but in certain veins, as the crural and the iliac, there are three of 
them together ; very rarely do they amount to four. In some in- 
stances there is but a single one ; this arrangement is more frequent 
at venous orifices, as the great coronary vein of the heart, the vena 
cava ascendens, the vena azygos. They are frequently found reticu- 
lated as if they had been lacerated, whence it has been supposed 
that the fibres which cross the sinuses of the dura mater are an 
elementary approach to them. 

The valves are more abundant in the superficial than in the deep- 
seated veins, but they do not exist every where. There are none 
in the branches of the vena portarum, excepting the vasa brevia: 
none in the spine, in the umbilical vein, the cervical veins, the kid- 
neys, womb, ascending and descending cava, or in the median vein. 
The valves are proportionately more abundant in the lower extre- 
mities. 

From the tenuity of the parietes of the veins, the blood may be 
readily distinguished circulating through them. Their coats, like 
those of the arteries, are vascular, or have the vasa vasorum. The 
arteries come from the nearest small trunks, while the corresponding 
veins do not empty immediately, but secondarily, into the trunk, 
whose parietes they supply. They are well furnished with veins. 

Their elasticity, both transversely and longitudinally, is well 
marked ; but they are not so extensible in the latter direction as the 
arteries, while they are more so transversely. There can be no doubt 
of their spontaneous powers of contraction, for it is abundantly proved 
by their diminishing much in volume upon the application of cold; 
moreover, when a venous trunk, distended with blood, is intercep- 
ted by two ligatures, and then punctured, it empties itself entirely 
and rapidly. 

The circulation in the veins is produced, in a principal degree, by 
the contraction of the heart; their own contraction may also favour 
this motion, as well as lateral pressure from contiguous parts. As 
the movement of the blood in the smaller arteries is so uniform as to 
be almost without pulsation, so the latter disappears entirely in the 
veins. It is not clear that this circumstance depends exclusively on 



THE BLOOD. 205 

the friction experienced by the blood in passing through the capil- 
laries, but is probably rather owing, as Mr. Hunter has suggested, 
to the veins receiving their blood from different arteries, some of 
whose channels are more circuitous than others, and, consequently, 
their blood arrives at different times. The momentum of the heart, 
then, even if it did impinge upon those channels, would not be syn- 
chronous upon the venous trunk, but would be divided in such a 
way as to produce a tremour or confused motion. The larger veins, 
however, have near the heart a pulsation during the contraction of 
the auricles, arising from the arrest of their circulation at the moment. 
During inspiration, the vacuum created in the thorax hurries on the 
blood to the heart, but in expiration it is somewhat impeded.* 

It has sometimes happened, that a large vein near the heart being 
opened by accident or an operation, a strong inspiration has caused 
the introduction of air, which, being carried to the heart, has pro- 
duced instant death. It occurred in Paris to the celebrated surgeon 
Dupuytren, and has occurred to others. 



CHAPTER IV. 



Of the Blood. 

The Blood is the fluid from which is derived the aliment for the 
growth and repair of all other parts of the body. It is renovated 
by the accession of new nutriment introduced into the system 
through the process of assimilation, and it has also a large increase 
from the decomposed materials of the several textures of the body. 

* This ancient observation has lately been renewed, with additional interest 
and details by M. Barry of Paris. See a Report of MM. Cuvierand Dumeril, 
concerning the Influence of the Atmosphere on the Circulation of the Blood, in 
the Philadelphia Journal of the Medical and Physical Sciences, for July, 1826. 
M. Barry has probably assigned too much importance to this influence, as it 
is certain that the circulation may go on very well where no vacuum is pro- 
duced at intervals in the thorax ; for example, in the foetus, in incubation, and 
in fish. 



206 CIRCULATORY SYSTEM. 

A copious excretion takes place from it through the different glands 
and emunctories. The precise manner of its formation is im- 
perfectly understood; it would at least seem to require no very 
complex apparatus for its formation, as it is generated in the area 
vasculosa of the germinal membrane of an egg, before the organs 
exist in a distinct state. 

The Blood, in the human subject, and in many animals, is of a 
red colour. It is about the consistence of thin size, has a peculiar 
smell, a nauseous and slightly saline taste, and is somewhat heavier 
than water; its specific gravity being about 105, and its temperature 
in the living body is from 96 to 98° of Fahrenheit. 

The method devised by Mr. Valentin to determine the exact 
proportion and quantity of blood in an animal has the merit of 
greater exactitude than any other, and seems to have solved this 
question with an accuracy almost unexceptionable. The weight of 
the animal is first ascertained ; a certain quantity of blood is then re- 
moved, and evaporated to dryness ; the w r eight of the residuum is 
then ascertained. A known quantity of water distilled is upon 
drawing the first blood, thrown in by the same orifice and allowed to 
mix with the general mass of blood. This done, a second quantity 
of blood equal to the first is withdrawn, evaporated to dryness also, 
and the weight of its solid residuum ascertained. The quantity of the 
residuum in the two parcels, determines the entire amount of blood 
in the animal by the following method : 

Thus, let two ounces of blood first draw r n yield twenty-four grains 
of solid matter ; and upon the injection of one pint and a half of 
w T ater let two other ounces of blood yield only twenty-one grains of 
solid matter. Then multiply the quantity of water injected by 
twenty-one and divide by three, (the difference in the two parcels 
of solid residuum :) the result will determine the whole quantity of 
blood in the animal after the extraction of the first two ounces. 
Thus 24 ounces multiplied by tw r enty-one and divided by 3, gives 
168 ounces. Tried by this method, a dog of 531bs. weight is ascer- 
tained to have ten and a half pounds of blood, and forty-two and 
a half pounds of other materials in his composition, or one part of 
blood, and four parts nearly of other constituents. 

There are some circumstances which may affect the absolute ac- 
curacy of the experiment, but the conclusion is so nearly satisfactory 
that Mr. Valentin in taking the dog as the standard for the human 
body fixes the quantity of blood in a man at thirty-four and a half, 



THE BLOOD. 207 

and in a woman at twenty-six pounds : the proportion in the first 
being, blood, 1 ; other parts, 4-30 : and for the female, blood, 1 ; 
and other parts, 4*93. 

A remarkable fact was observed in an emaciated and diseased 
dog, that the relative quantity of blood to other parts was the same 
as in health. 

If the blood be examined microscopically while circulating in an 
animal, or immediately upon being drawn, it is seen to consist of 
red particles or globules swimming in a transparent fluid. This 
transparent fluid is the Liquor Sanguinis or Plasma, which is formed 
of serum and fibrin, the latter being in a state of solution in the 
serum. This state of solution has been proved by Muller in filter- 
ing through a porous paper the blood of a frog recently drawn : from 
the size of the red particles they are in this process left behind and 
the serum and fibrin passing through together, the fibrin forms a 
coagulum* to itself. The proportion of fibrin in the human subject 
to the entire mass of blood would seem to be very small, as in the 
experiments of Lecanu he found fibrin, when dried, to form from 
about one and a third to seven parts, in one thousand. 

In a spontaneous coagulation the fibrin attaches itself to the red 
globules and is found with them, while the serum separates and is 
squeezed out. 

So long as it continues to circulate, or while it is still flowing 
from an opened vessel, the blood has, to common inspection, the 
appearance of a homogenous fluid ; yet, after it has been drawn a 
few minutes, and permitted to remain at rest, it assumes a thick ge- 
latinous condition, expressed by the term coagulation, and by which 
it ceases to be any longer fluid. The coagulation begins on the sur- 
face of the mass, and by a thin pellicle, which shows itself in three 
or four minutes ; commonly at the end of twenty minutes the coagu- 
lation is complete throughout, but this rule varies according to the 
state of the body at the moment ; and the coagulation is more pro- 
tracted when the quantity of blood is large and has been drawn 
through a large orifice, than where it is small, and has been evacu- 
ated through a small orifice. This change has scarcely taken place, 
when a spontaneous separation follows, whereby it is resolved into 
the watery part, or Serum, and into a thick condensed mass called 
Cruor or Crassamentum. The serum first shows itself on the sur- 

* Physiology, p. 124. 



208 CIRCULATORY SYSTEM. 

face of the coagulum, in small drops, which quickly increasing in 
number and size, finally run together, and form a mass of fluid ex- 
ceeding considerably that of the crassamentum. The separation into 
serum and crassamentum, though sufficiently evident after a few 
hours, yet requires some days for its complete accomplishment ; for 
the coagulum still continuing to contract, expels more and more of 
the serum. 

The peculiar complexion of the blood depends upon the red glo- 
bules. They do not seem to be an indispensable constituent, as 
many animals are entirely deprived of them, and such as naturally 
are possessed of them, may have their quantity very much reduced 
by repeated bleedings. The colouring matter is generally an in- 
gredient of the crassamentum, so that the whole of the latter has a 
red appearance ; yet there are some conditions of the body in which 
a spontaneous separation of it takes place, more or less completely. 
For example, in inflammatory diseases the blood does not coagulate 
so soon as in health ; and the red globules, from being naturally 
heavier than the other constituents of the crassamentum, subside to 
its bottom and leave it of a white semi-transparent colour. It is 
this white part upon which depends the whole property of coagu- 
lating, and which has been called coagulating lymph, or fibrin. We 
have, therefore, three constituents of blood manifested by its own 
spontaneous changes ; the Serum, the Red globules, and the Coagu- 
lating lymph. 

As in inflammation the red particles subside to the bottom before 
the coagulation of the fibrin begins, the fibrin is seen more largely 
on the surface of the clot, and by a strong contraction in coagulating 
draws the top of the clot into the form of a saucer. There is, how- 
ever, always a little fibrin left throughout the clot, and holding the 
red particles together ; with the exception of a few which may be 
found at the bottom of the vessel, perfectly untrammelled by it. It 
was ascertained by Sir C. Scudamore that inflammatory blood con- 
tained more fibrin than healthy blood. 

Coagulation, contrary to popular opinion, is not assisted by cold, 
but rather retarded by it : heat assists it.* If the heat be raised to 
120°, blood will coagulate five minutes sooner than if left at its na- 
tural standard, and even sooner than if its temperature be reduced 
to 50°. If blood be frozen quickly, before it has time to coagulate, 

* Hunter on the blood. Hewson. 



SERUM OF THE BLOOD. 209 

on being thawed it returns to the fluid state, and will coagulate after- 
wards. The contact of air does not produce coagulation. The late 
Dr. Physick, in order to ascertain this point conclusively, took a glass 
tube, which had a stop-cock at each end, and attached one of its ends 
to the vein of a dog. A current of blood was then conducted through 
the tube, and while it was flowing, the far stop-cock was closed, and 
immediately afterwards the other ; thus, a column of blood was ob- 
tained which had not touched the air. After permitting it to remain 
a proper time, the tube was broken asunder, and the blood found 
coagulated as usual. Rest is not indispensable to the process, for 
blood, if shaken in a vial, will still coagulate. The division of the 
blood into small masses expedites coagulation. Therefore when it 
flows slowly from the blood vessels, falls from some height, or runs 
for a distance over the surface of a dish, it coagulates sooner than 
under opposite circumstances. The latter are then auxiliary to the 
blood manifesting the sizy coat, one of the concomitants of inflam- 
mation ; because if the coagulation be very rapid, it will prevent the 
constituents of the crassamentum from separating from one another, 
by entangling the red globules, in the coagulating lymph. 

After death the blood is coagulated in the veins, though not so 
perfectly or generally as is supposed, for there are no subjects 
which do not bleed from their large veins, when the latter are 
opened. 

The coagulation of the blood is sometimes delayed for many 
hours after death. I have in examining the head of a patient 
who died of phthisis pulmonalis found the blood which came from 
the jugular veins, in a thin fluid state and of a bright vermillion 
colour ; and upon being spread out on a plane surface it coagu- 
lated like recent blood. 

There are many modes of death which prevent entirely the coagu- 
lation of the blood in the vessels, for example, where life is destroyed 
by a paroxysm of excessive anger ; by electricity ; by lightning ; by 
a blow upon the stomach ; by certain fevers of a typhoid character. 
Many chemical articles prevent its coagulation on being mixed 
with it. v 



SECT. I. — OF THE SERUM OF THE BLOOD. 

Serum is common to the blood of all animals, and is considered, 
by Mr. Hunter, to be more abundant in such as have red globules. 
Vol. II.— 19 



210 CIRCULATORY SYSTEM. 

It is, generally, of a lighter specific gravity than the crassamentum. 
I have, however, often seen the latter floating in it, which shows the 
contrary in some instances. Though its separation commonly de- 
pends upon the coagulation of the latter, yet that process is not in- 
dispensably necessary, as was once witnessed, by Mr. Hunter, in a 
lady, in whom the serum was disengaged from the crassamentum, 
while the latter was yet in a fluid state. The phenomena of dropsy, 
also, prove the same point. 

Serum though very fluid, is not so much so as water. It is of a 
light yellow or straw colour, varying, somewhat, in different subjects. 
It contains a large quantity, about eight per cent., of albumen, or 
matter resembling the white of an egg. It also consists of water, 
about ninety per cent.; of soda uncombined, and of several of the 
salts of soda, the presence of which may be manifested in several 
ways. For example, when exposed to a heat of 140 degrees of 
Fahrenheit, it becomes opaque, and at 160 or 165 coagulates firmly. 
During this process, a great deal of air is disengaged from it. It is 
also coagulated by spirits of wine, by all the mineral acids, by cor- 
rosive sublimate, and by many other articles. They all prove the 
presence of albumen. Mr. Brande considers the albumen as an 
albuminate of soda, and that its fluidity depends on the excess of 
soda; when, therefore, the latter is removed or neutralized by an 
acid, the albumen coagulates. Under the action of the Galvanic 
pile, like the influence of heat, the soda produces mucus, by blend- 
ing with a part of the albumen ; and the remainder of the latter, not 
being able to retain its fluidity after the abduction of the soda, 
coagulates. 

This mucus or serosity is, probably, the part which Mr. Hunter 
speaks of as retaining its fluidity when other portions of the serum 
are coagulated by heat. It is observed in meat either roasted or 
boiled, and comes from it as a thin, limpid fluid, somewhat tinged 
with the red globules. The older the animal is, the greater is its 
comparative quantity: in lamb, there is scarcely any of it, whereas, 
in mutton five or six years old, it is abundant ; the same rule seems 
to hold in regard to the human subject. This serosity, or mucus, 
is coagulable by Goulard's extract.* 

The serum is not always transparent, but sometimes wheyish and 
thin: when it settles, it often throws up a white scum like cream and 
'•ailed Seroline. This more frequently occurs in pregnant women, 

* Hunter, loc. cit. 



COAGULATING LYMPH OF THE BLOOD. 211 

though it is not confined exclusively to either sex, or to any known 
condition of body. The specific gravity of the globules composing 
this seroline varies ; for though it generally floats on the surface of 
the serum, it does not always : it also sometimes swims, and, on 
other occasions, sinks in water. It has been erroneously considered 
as chyle not yet assimilated, or as absorbed fat or oil. It is, proba- 
bly, this substance which presents itself under the form of micro- 
scopic globules in the coagulum of serum ; and, when serum has been 
kept for several days, is deposited in the form of globules at its 
bottom. These globules present a singular motion of ascent and 
descent in the serum ; upon the application of heat to it by holding 
in the hand. 

The presence of soda uncombined in the serum, is readily ascer- 
tained by an infusion of red cabbage, (Brassica oleracea,) or the juice 
of the flag, (Iris versicolor,) which are both made green by it. Sul- 
phur combined w T ith ammonia, is also found in it. Owing to the 
presence of sulphur, serum has the effect of blackening silver when 
left in it, and also has its power of dissolving the oxydes of mercury, 
iron, copper, and other metallic preparations. 

The serum contains a portion of fatty matter allied to the same 
substance in other parts of the body, and which may be extracted 
with ether. It also contains animal principles, whose general de- 
signation is that of extractive matter, and some of the ingredients of 
which are lactic acid and osmazome. They are believed by Ber- 
zelius to be the effete parts derived from the continual decomposition 
of the body, and which are conveyed away through the excretions. 
There are some other salts besides those mentioned which are found 
in serum.* 

The serum has a specific gravity in health of about 1030, and con- 
tains about 9h per cent, of solid matter including the albumen — the 
seroline and the mineral constituents. 



SECT. II. — OF THE FIBRINE OR COAGULATING LYMPH OF THE 

BLOOD. 

Coagulating lymph, or fibrine, when circumstances are suitable 
for collecting it free from the red globules, offers the appearance of a 

* See Henle, Anat. Gen. t. i. p. 483. 



212 CIRCULATORY SYSTEM. 

semitransparent body of a very light drab colour ; it is elastic and 
strong, and when subjected to the microscope, has the appearance 
of muscular fibres, by being composed of colourless globules. Like 
muscle, it also, when macerated in water, resolves itself into those 
globules before it putrefies. 

If the blood, w : hile flowing from an animal, be collected, and, at 
the same moment, stirred around and around with a rough stick, the 
fibrine will gather upon the latter in a fibrous form, so as to resemble 
a mass of entangled and knotted packthread. The fibrine may be 
afterwards washed almost white, and, at any rate, so as to clear it 
entirely from the red globules. 

The fibrine, w T hen dried, loses greatly in its bulk and weight, by 
the evaporation of the serum from it, so that the proportion which 
it seems to bear to the whole mass of blood, is much less considera- 
ble than one would suppose, from seeing it in the simple coagulated 
state. 

The coagulating lymph of the blood being common, probably to 
all animals, while the red particles are not, we must suppose it from 
this alone to be the most essential part ; and, as we find it capable 
of undergoing, in certain circumstances, spontaneous changes, which 
are necessary to the growth, continuance, and preservation of the 
animal ; while to the other parts we cannot assign any such uses ; we 
have still more reason to suppose it the most essential part of the 
blood in every animal."* 

In examining a drop of blood with a deep object glass, there is 
apparent in the field of vision one or two white globules, the average 
diameter of which is about s/os of an inch. They are either smooth 
or granulated on the surface, semitransparent and spherical, or nearly 
so. They differ from the blood discs, or red globules, in being 
nearly the same in all animals, they are more obscure in the human 
subject and mammalia, but are very distinct in reptiles, birds, and 
fishes. They were first seen by Spallanzani in the Salamander, and 
then noticed in the blood of Mammalia, by M. Mandl, a few years 
ago ; they are considered by the latter as produced by a coagulation 
of fibrin, and, as identical with the globules of pus and mucus. By 
Mr. Gulliverf they are called nucleated cells or organic germs of 
fibrin : he is, however, doubtful of their perfect identity with the 
particles quoted by Mr. Mandl. 

* Hunter, loc. cit. 

f Appendix to Gerber's Gen. Anat., p. 14. 



RED GLOBULES OF THE BLOOD. 213 

Besides the above, Mr. Gulliver has seen a white matter existing 
in abundance in the form of spherules, of from 4,^ to T 4 TT " of an 
inch. The animals in whom it was witnessed had died chiefly of 
tubercular phthisis, and he, therefore, is inclined to think this a pa- 
thological appearance. 

Besides milky serum, which is sometimes found in the blood after 
a repast, corpuscles of a peculiar kind have been noticed in the 
splenic and supra renal veins, which are supposed to come from the 
spleen and from the capsulae renales.. 



SECT. III. — OF THE RED GLOBULES OF THE BLOOD.* 

The impression at the present day in regard to the red globules, 
or Blood discs, as they are also called, is that they are flattened bodies 
of a circular shape and having a thickness from a fourth to a half of 
their breadth. To see them of this figure, they should be ex- 
amined in fresh serum, a weak solution of common salt, or in thin 
syrup ; if water alone be used they contract into a spheroidal shape. 
In birds, reptiles, and fishes they are elliptical. 

In the lower orders of animals the disc appears to have a central 
nucleus, which projects in a rounded form above the general surface 
of the disc. In the siren, according to Professor Owen, the disc 
consists of from twenty to thirty spherical granules. But very great 
doubt exists in regard to the nucleus in man and the mammalia gene- 
rally. Authority of the highest kind may be quoted for either opi- 
nion. Mullerf says he has seen it, Carpenter is inclined to admit 
it, Gulliver} denies, and Wagner who once admitted it, now holds 
it as uncertain, Henle§ says, that, drying renders the nuclei of 
the corpuscles of the blood very obvious, and that in calcining them, 
the wrecks of the nucleus and feeble traces of the envelope, are dis- 
cernible. This is the result of his observations on the lower orders 
of vertebrata, but in the human subject and mammalia, he evidently 
disinclines to the opinion of nuclei existing in the blood discs. He 
says, in one place that the pretended nucleus is only the depressed 

* Anat. Alias, Figs. 434, 435. 

f Page 115. 

£ Appendix to Gerber, p. 15. 

§ Encyclop. Anat., vol. vi., p. 466. Paris, 1843;. 

19* 



214 CIRCULATORY SYSTEM. 

centre of the disc, and in another place, he says, that in all his ex- 
periments, it has scarcely ever occurred to him to see any trace of 
nucleus. — Numerous opinions for and against may thus be cited, and 
while the question is agitated by the best observers, others may very 
properly await their decision. 

Under common observation the light transmitted through the 
centre of the blood discs is more intense than elsewhere, which gives 
to them the appearance of being perforated or annular. 

By many, each blood disc is considered, notwithstanding the diffi- 
culties of determining such minute points of structure in the human 
body, to consist in a capsule, a contained matter, and a nucleus in 
its centre. The advocates of this opinion, also view it as a de- 
termined fact, that the blood discs conform in their general character 
with the isolated cells, which constitute the whole of the simplest 
plants, each having an independent life of its own. 

The improvements of the compound microscope have enabled us 
to determine with accuracy, the diameter of the blood discs or red 
globules. It appears now that there is no absolute or uniform size 
to them in the same mass of blood, but that they vary much in this 
respect, some being about fj^ of an inch, and others about the 
. ' . Other animals than man present them of a larger or smaller 
size, thus in the fish called Squalus Squatina, they are about the 
— J — of an inch, whereas, in the cat they measure about — ! — . 

1000 ' ' J 7000 

The different magnitudes in man are supposed to be accounted 
for by admitting them as cells in various stages of growth and evo- 
lution. Their size has no relation to the magnitude of the animal, 
fur in the Mouse they have three times the diameter of those of the 
Musk deer. 

The proportion of blood-discs varies very much in different persons : 
the average is about 140 in one thousand parts of blood in the male, 
but it may go to 186 or descend to 110 without ill health. In the 
female the average is about 112 in the thousand, but it may fall to 
71 or rise to 167 in common health. In chlorosis it has been found 
as low as 27, and not unfrequently is at from 40 to 50 parts in the 
thousand.* 

The blood corpuscles, or blood discs, are larger in the embryo 

Jian in the adult, Mr. Prevoet has seen that they were in the foetal 

* twice the size of such as belonged to the maternal. Mr. Barry 

* Carpenter's Elera. of Physiol, p. 309. 



RED GLOBULES OF THE BLOOD. 215 

asserts, that the germinal state of every tissue is that of corpuscles, 
having the same appearance with the blood corpuscles, and Mr. 
Gulliver, that they are much more abundant in inflammatory diseases 
than in health. 

It has been already observed that the red globules are the heaviest 
part of the mass of blood, and are, therefore, always disposed to 
subside to the bottom of the crassamentum, though from the quick 
coagulation of the latter, they can seldom do it fully before they 
become entangled in it, and thereby fixed to a certain place. They 
do not invariably retain their form, but are readily dissolved in 
water. They are, of course, insoluble in serum. Urine does not 
dissolve them; neither does a solution of muriate of soda, of sal 
ammoniac, epsom salts, nitre, diluted sulphuric or muriatic acid: 
the latter, however, deprives them of colour. 

The solution of red globules in water is manifested by the mixture 
becoming of a fine transparent red, and the process takes place 
almost immediately. On the contrary, when the globules refuse to 
be dissolved, a muddy mixture is formed. When they are dried in 
serum, and afterwards soaked again in it, they do not resume the 
regular form. They have more substance than the coagulating 
lymph, for they do not lose so much of their bulk by drying. 

The analysis of the blood corpuscles presents two proximate prin- 
ciples, hcematosin and globulin. The first amounts to about <sV or 
2*5 of the mass when the globules are dried, and when burned, it 
yields a quantity of peroxide of iron. 

The colouring ingredient of the red globule, is commonly con- 
sidered to be the peroxide of Iron. In some recent experiments of 
Mr. Scherer, this belief has been assailed, if not invalidated, by his 
observing, that though the iron be removed, yet alcohol can be 
made intensely red by boiling in it the globules left after such ex- 
traction. 

" It is difficult to determine by what means the iron, or the sul- 
phur, or the elementary principles of the calcarious earths, obtain an 
existence in the blood. If these materials were equally diffused 
throughout the surface of the earth, we might easily conceive that 
they were introduced through the medium of food. But as this is 
not the case, as some regions, like New South Wales, at least, on 
this side the Blue Mountains, contain no limestone whatever, and 
others, no iron or sulphur, while all these are capable of being ob- 
tained apparently as freely from the blood of the inhabitants of such 



216 CIRCULATORY SYSTEM. 

regions, as from that of those who live in quarters where such ma- 
terials enter largely into the natural products of the soil: it is, per- 
haps, most reasonable to conclude that they are generated in the 
laboratory of the animal system itself, by the all-controlling in- 
fluence of the living principle."* 

The red globules, according to the opinion of Mr. Hunter, from 
not being pushed into the extreme arteries, where the coagulating 
lymph reaches, and from not being found in all animals, do not con- 
tribute to the growth and to the repair of the system. But they seem 
to be connected with strength, in such animals as have them, as the 
strength acquired by exercise increases their proportion and occa- 
sions them to be carried abundantly into parts which previously, from 
a debilitated state, received them but partially if at all. This fact 
is well known to graziers, who keep their quantity in certain animals, 
as veal, reduced by quietude and frequent bleeding. 

Their source is not understood, though many conjectures on the 
subject have been hazarded. 

Leeuwenhoeck asserted, that they had the power of self-repro- 
duction, and this statement has received additional confirmation by 
the observations of Mr. Barry.f According to him the propagation 
takes place by the parent globule splitting into about six others, the 
development starting from its nucleus. As there is a continual de- 
composition going on, each disc or cell has a definite period of 
existence, and while some are dying others are coming into exis- 
tence. 

Mr. Hunter's opinion was, that they do not appear to be formet 
in those parts of the blood already produced, but rather to rise up 
in the surrounding parts : as, in the incubated egg, they exist in the 
form of a zone, composed of dots, previously to the formation of 
vessels. 

The above sentiments of a very celebrated man, it may be well 
enough to preserve, though they seem to be in contradiction with 
present views, except the appearance at first in the incubated egg. 

The analysis of Mr. Lecanu, in regard to all the elements, organic, 
and inorganic, entering into the composition of the blood, is regarded 
as having a high claim to confidence. The blood was obtained in 
two parcels, each from a stout healthy man: 

* Good, Stud, of Med. 

t Phil. Trans. 1840, and 1841. 



RED GLOBULES OF THE BLOOD. 



217 



Water 

Fibrin 

Albumen 

Colouring matter, (globules) 

Fatty crystallizable matter 

Oily matter 

Extractive matter, soluble in water 

and alcohol 
Albumen combined with soda. 
Chloride of Sodium 

" potassium 

Carbonates } of Potash and Soda 
Phosphates > " " 

Sulphates ) " « 

Carbonates, Lime, and Magnesia 
Phosphates, Lime, Magnes. and Iron 
Peroxide of Iron 
Loss 



780.145 


785.590 


2.100 


3.565 


65.090 


69.415 


133.000 


119.626 


2.430 


4.300 


1.310 


2.270 


1.790 


1.920 


1.265 


2.010 



J 



8.370 

2.100 
2.400 



7.304 

1.414 

2.886 



1.000.000 



1.000.000 



Denis found the proportion of water in man's blood to vary from 
805 to 732 in a thousand parts, and in woman from 848 to 750. 
According to Lecanu, the quantity of water bears no determined 
relation to the period of life ; Denis, however, found it more abun- 
dant in children, and in aged persons. In sanguine temperaments 
the blood has less water in it than in lymphatic. 

The proportion of albumen varies from 57.890 to 78.270, and is 
about the same in the two sexes. The crassamentum consisting of 
the red globules and of fibrin, varies from about 68.349, to 148.450, 
and in men it is more abundant than in women, in the proportion of 
32.980 parts in the thousand.* 

* For very erudite and interesting Essays on the blood in regard to its cor- 
puscles, liquor sanguinis or plasma, quantitative analysis, development, re- 
generation, and other points connected with it, a full account of which would 
be too long for the present work ; the reader is referred to the writings of 
Hewson and Hunter, in the last century. Henle's Gen. Anat. p. 457, et 
seq. Paris, 1813. Muller's Physiology, by Baly, p. 109, et seq. vol. i. London, 
1842. Principles of Human Physiology, by W. B. Carpenter, p. 464, et 
seq. London, 1842. Wagner's Elements of Physiology, by Willis, p. 230. 
London, 1842. Animal Chemistry by Dr. J. F. Simon. Phila. 1846. 



BOOK VIII. 



PART II. 

OF THE SPECIAL AMATOMY OF TIIE CIRCULATORY SYSTEM. 
CHAPTER I. 

Of the Heart and Pericardium.* 

The Heart, (Cor,) the centre of the circulation, is situated in the 
thorax, between the sternum and the spine ; being bounded on its 
sides by the lungs, and below by the tendinous centre of the dia- 
phragm. It is a hollow muscular organ. 

The heart is of a conoidal shape, but flattened on the surface 
which lies upon the diaphragm. This flat surface is on a horizontal 
line with the lower end of the second bone of the sternum ; the base 
of the cone is towards the vertebrae, and looks obliquely backwards 
to the right side, while the apex is about the junction of the left fifth 
rib with its cartilage. Its common weight is about six ounces. Its 
greatest length, to wit, that from the apex to the base, is about 
five and a half inches, four of which are taken up by the ventricles : 
its base is about three and a half inches in diameter. 

The heart is divided into four cavities ; two auricles and two ven- 
tricles : the places where the partitions are placed between these 
cavities are marked on the surface of the heart by fissures or depres- 
sions, sufficiently distinct to be immediately recognised. The two 
auricles form the base of the heart, the ventricles constitute its body, 
and the anterior end of the left ventricle, by being extended somewhat 

* Anat. Atlas, Figs. 439 to 447, inclusive. 



220 CIRCULATORY SYSTEM. 

beyond the right forms the apex. The right auricle and the right 
ventricle, are the two cavities which are nearest to the right side of 
the body, while the left auricle and the left ventricle are the two 
cavities nearest to the left side. It will, however, be understood, 
from the general observations already made, that the relative situa- 
tion of these cavities is such, that the right ones are in front of the 
others, and present obliquely forwards to the right side, while 
those on the left look obliquely backwards to the left side. This 
position of the heart makes it encroach more upon the left cavity of 
the thorax than it does upon the right ; from which cause its pulsations 
may be very easily distinguished where the left ribs join their car- 
tilages, while on the right side of the sternum there is scarcely ever 
a perceptible pulsation. Being placed between the right and the 
left pleura, in the mediastinum, it is surrounded by its own proper 
capsule called the Pericardium. 

The Pericardium is covered on its sides by the Pleurae, and re- 
poses on the tendinous centre of the diaphragm, to which it adheres 
by close compact cellular substance, particularly at its periphery. 
When the latter attachment is cut through, a separation of the re- 
mainder is easily effected. Behind, the pericardium is opposite to 
the bronchia and to the oesophagus. 

The pericardium does not adhere to the heart, except at the base 
of the latter ; it is, therefore, a loose capsule in, by far, the greater 
part of its extent. It not only surrounds the heart, but also the roots 
of the large arteries and veins connected with it. Thus, it includes 
the aorta, as high up as the great vessels proceeding from its arch ; 
from the latter, it passes to the trunk of the pulmonary artery, and 
also includes it, causing the aorta and the pulmonary artery to lie 
close together. The posterior face of these vessels is not covered 
so high up as the anterior face. The pericardium also invests the 
descending vena cava for an inch above its junction with the right 
auricle : it likewise invests the trunks of the pulmonary veins, and 
the ascending cava as it rises above the diaphragm. The pouches 
which it forms at the base of the heart, in passing from one of these 
vessels to another, are the cornua of some anatomists. It cannot be 
considered as pierced for the passage of these vessels, but is lost 
insensibly on their parietes ; being continued into the cellular cover- 
ing of the arteries, in accompanying them to a great distance.* 

* Sabatier, Trait. d'Anat. vol. ii. p. 284. 



PERICARDIUM. 221 

The pericardium is a double membrane, or consists of two layers, 
an internal and external one. The external membrane, to which 
the preceding description is especially applicable, resembles strongly 
the dura mater, but is thinner; it is, therefore, white, semi-transpa- 
rent, fibrous, and inelastic. Its thickness is greater on the sides, 
than below where it rests upon the diaphragm; or above, where it 
goes along the great vessels : its fibres are irregularly disposed and 
interwoven, but many may be traced longitudinally. 

The Internal layer lines the external, and gives the polish to its 
cardiac surface ; it is then conducted along the surface of the seve- 
ral vessels that have been mentioned, to the heart, over the whole 
of which it is spread, and adheres to it by cellular substance, fre- 
quently containing much adipose matter: it also causes the heart 
to have a smooth shining surface. This is a very delicate thin 
serous layer; and secretes a fluid, transparent and somewhat 
unctuous, like that of the joints, but not so consistent; which lu- 
bricates the surface of the heart and permits it to play freely within 
its pericardium. This fluid, in a natural state, seldom exceeds a 
tea-spoonful, though two ounces, or a little more, are not considered 
sufficient evidence of a pathological state: its augmentation consti- 
tutes a dropsy. 

After death, we find jhe pericardium lying loosely around the 
heart, from the vacuity, and consequently diminished bulk of the 
latter; but while the circulation is going on, the heart fills and 
distends it. A striking resemblance is observable between the 
condition of the pericardium and the moveable articulations. Its 
external layer corresponds with the strong fibrous capsule that 
passes from one bone to the other ; while the internal is the syno- 
vial bag, which scarcely assists in the strength of the apparatus, 
but secretes a fluid to render motion easy. 

Several instances are on record of a total absence of pericardium. 

The Right Auricle {Auricula Dextra, Anterior) is an oblong cu= 
boidal cavity. It is joined at its posterior superior angle by the de- 
scending vena cava, and at its posterior inferior angle by the ascend- 
ing vena cava. The structure of the auricle, between these wet 
points, seems to be only a continuation of that of the veins. These 
veins enter with a direction slightly forwards, so that their columns 
of blood are not directly opposed to each other. In front of this 
continuation of the two veins, the auricle is dilated into a pouch 

Vol. II.— 20 



222 CIRCULATORY SYSTE1VL 

called its Sinus : the upper extremity of the latter, just in front of 
the descending cava, is elongated into a process with indented 
edges, and has some general resemblance to the ear of an animal, 
from which it is probable that the term Auricle has been derived. 

The exterior surface of this cavity is smooth and uniform, but 
its internal surface is varied at several places. About midway be- 
tween the orifices of the two cavse is found a transverse prominence, 
the Tuberculum Loweri, which is occasioned by the continuous 
structure of the veins meeting at an obtuse angle. This cavity is 
separated from the left auricle only by a thin septum, which is com- 
mon to the two auricles. On the septum, below its middle, is a 
superficial circular depression, the Fossa Ovalis; it is more distinct 
above than below, and varies much in its dimensions. It is sur- 
rounded by an elevated margin, composed of muscular fibres, and 
called its Annulus, or the Isthmus of Vieussens. The septum of the 
auricles is thinner at the fossa ovalis than elsewhere, and is fre- 
quently perforated by one or more foramina. I have, in several 
instances, seen a hole there, large enough to transmit the finger. 
On such occasions, from the valvular arrangement of the opening, 
it is probable that the blood of the tw T o auricles is stillkept distinct. 
The fossa ovalis always presents this foramen in the foetal state. 

Just below the fossa ovalis is found the Eustachian valve, con- 
sisting in a duplication of the lining membrane of the auricle. It is 
crescentic, but varies much in its dimensions and shape. Its left 
extremity commences at the left inferior margin of the annulus 
ovalis ; it then extends itself along the front of the orifice of the as- 
cending cava, where the latter is connected with the auricle, but 
never to an extent sufficient to arrest the circulation there. Some- 
times it is reticulated at its margin, and half an inch wide ; on other 
occasions, it is scarcely developed. Its loose edge looks upwards, 
and to the right side. Its office in the foetus is clearly, according 
to the opinion of Sabatier, to direct the blood of the ascending cava 
through the foramen ovale. In the adult, it may, on the general 
principle of venous valves, oppose itself to the introduction of re- 
fluent blood into the ascending cava; but this office cannot be very 
exactly performed, as the valve is frequently scarcely visible at that 
age. 

At the lower part of the right auricle, just to the left of the 
Eustachian valve and very near it, is the orifice of the large coro- 



THE HEART. 223 

nary vein of the heart : it is protected by a small semi-lunar valve, 
(Valvula Thebesii,) formed also by a duplication of the lining mem- 
brane of the auricle. This orifice will admit a quill of common size 
very readily. 

At the anterior semicireumference of the descending vena cava, 
there is an oblique fasciculus of muscular fibre, with which the ad- 
joining musculi pectinati are connected, and which in its contrac- 
tion will answer, to a limited degree, as a valve or barrier, in pre- 
venting the reflux of blood from the auricle into the cava. A smaller 
fasciculus of muscular matter also exists along the base of the Eu- 
stachian valve, and will execute the same office for the ascending 
cava. The office however of neither is perfect, but limited to a 
partial state of occlusion. 

Between the right auricle and ventricle is a round hole, of more 
than an inch in diameter, for the passage of the blood ; it is the 
Ostium Venosum. Its margin, on the auricular side, is smooth 
and rounded. 

The parietes of the right auricle are formed by muscular fibres. 
On the Sinus these fibres are collected into small transverse fasci- 
culi, called Musculi Pectinati, from their resembling the teeth of 
a comb. These fasciculi, though slightly united by other fibres, 
yet leave between them deep interstices, by which the external 
and the internal membrane of the heart come into contact. The 
parietes of the auricle are about one line in thickness. Its mus- 
cular structure is continued for a short distance, on the two vena? 
cava. There are several orifices of small veins on the internal 
surface of this cavity, and in greater abundance around the fossa 
ovalis ; they belong to the system of coronary vessels, and are the 
foramina Thebesii. 

The Right Ventricle ( Ventriculus Dexter, Anterior.) The general 
form of this cavity, which receives the blood from the right auricle, 
is that of a triangular pyramid, curved somewhat backwards, and 
having its base downwards. It forms the greater part of the ante- 
rior surface of the heart, and is about three lines in thickness. It 
is bounded on its posterior face by the left ventricle, from which it 
is completely separated by a thick septum. 

The internal surface of this cavity is covered by muscular fasciculi, 
of very irregular shapes and dimensions, designated under the term 
Columnar Carnece : some of the latter go from one side to the 



224 CIRCULATORY SYSTEM. 

other ; others contribute to the mechanism of the valvular apparatus 
between it and the right auricle ; but the greaterportion is employed 
in forming a complicated reticular texture over the internal face of 
the ventricle. Those connected with the valve vary from four to 
eight in number : they are rounded, of different lengths and sizes, 
and detach from their projecting extremities several small rounded 
tendinous chords, [Chorda tendinece,) which are inserted into the 
floating edge of the valve. These chords form an intertexture 
among themselves. 

The Valve, between the ventricle and the auricle, consists in a 
duplicative of the lining membrane of the ventricle, arising unin- 
terruptedly from around the ostium venosum, at the left margin, 
which is there somewhat tendinous. This valve is called the Tri- 
cuspid, (Valvula Tricuspis, Triglochis,) because its loose margin 
is divided into three points or processes. One of these points, 
which is at the anterior external margin of the orifice, is much 
larger than the other two and more distinct in its boundaries. 
The edges of these processes form a sort of reticulated work along 
with the adjoining ends of the tendinous chords: by this arrange- 
ment they are always kept expanded and in the cavity of the ven- 
tricle. 

The opening for the pujftionary artery is placed above the ostium 
venosum ; at this point, the cavity of the ventricle, instead of being 
reticulated, is made smooth, for the more ready transmission of 
blood. The orifice of the pulmonary artery is round, and about 
twelve lines in diameter ; it is furnished with three valves, called 
from their shape Semi-lunar or Sigmoid. Each valve is a semi- 
circular plane, formed from the lining membrane of the artery, and 
attached to the latter by its semi-circumference. The diameter of 
the plane is loose, and, instead of being straight has each semi- 
diameter of a curved or festooned shape : in the centre of its edge 
is a small cartilaginous body, the Corpusculum Aurantii, which when 
the valve is thrown down by the reaction of the artery, comes in 
contact with the corresponding bodies of the other valves, so that 
they serve as mutual abutments. The Corpusculum is some- 
times scarcely discernible. Between the outer face of each valve 
and the artery there is a pouch, attended with a slight dilatation of 
the artery, and called the Sinus Valsalvae. Between the coats of 
each valve there is an additional fibrous substance, for the purpose of 
strengthening it. 



THE HEART. 225 

The Pulmonary Artery, immediately after its origin, goes up- 
wards and backwards to the under part of the curvature of the aorta, 
and there divides into two trunks, one for each lung. These trunks 
separate widely, and from the middle of their fork proceeds a liga- 
mentous substance, the remains of the Ductus Arteriosus of the foetus, 
to the aorta posteriorly to the origin of the left subclavian artery. 
The right Pulmonary artery is both longer and larger than the left, 
and passing transversely behind the aorta and the descending cava, 
then penetrates the substance of the lung to be distributed as men- 
tioned. The left pulmonary artery passes to the lung in front of the 
descending aorta. Though the pulmonary artery is quite as large 
as the aorta, its parietes are thinner. 

The Left Auricle, (Auricula Sinistra, Posterior,) in the natural 
situation of the heart, is concealed by the right auricle and the ven- 
tricles. Its figure is more regularly quadrangular, or square, than 
that of the right, and into each of its angles is introduced a pul- 
monary vein, there being two on each side. Sometimes, however, 
the latter join together previously, so that the two have but a com- 
mon orifice. Its tip, or ear-like portion, is situated at the left side 
of the pulmonary artery, and is longer, narrower, more crooked, 
and more notched at its margins than the corresponding portion ol 
the right auricle. 

The parietes of this cavity are muscular, and somewhat thicker 
than those of the right ; they are smooth and uniform, both exter- 
nally and internally, with the exception of its appendix or ear-like 
portion, in which the musculi pectinati prevail. The term Sinus 
Venosus or Sinus Pulmonalis of anatomists, only means that part of 
the cavity into which the pulmonary veins empty. The septum be- 
tween the auricles, when viewed on this side, has the place of the 
fossa ovalis marked out principally by its diaphanous condition. 
Occasionally, there is some appearance of the valve which once 
existed there. 

At the inferior part of the anterior side of this cavity is found the 
opening between it and the left ventricle, also called Ostium Veno-. 
sum ; it is circular, and rather more than an inch in diameter, re-, 
sembling strongly the corresponding orifice of the right side of the 
heart. 

The Left Ventricle (Ventriculus Sinister, Posterior) in the shape 

20* 



226 CIRCULATORY SYSTEM. 

of its cavity resembles a long ovoidal or conical body. Its parietes 
are generally three times as thick as those of the right ventricle, 
amounting to about eight lines : it is thicker, however, at its inferior 
than at its superior part, as it gradually decreases in approaching 
rhe aorta. 

Its internal surface is arranged on the same principle with that of 
the right ventricle, being roughened by the presence of numerous 
fleshy columns (Columna Cameo) some of which are connected 
with the valvular apparatus between it and the left auricle : others 
form an intricate reticular texture on its sides, and a few pass from 
one side to the other. As this surface approaches the orifice of the 
aorta, it becomes smooth, so that no impediment may be afforded 
to the passage of the blood. 

The Ostium Venosum, on the side of this cavity, has its margin 
rooking tendinous, and furnished with a duplicature of the lining 
membrane that surrounds it. This duplication, by being severed 
on its loose edge into two divisions, obtains the name of Mitral 
Valve, {Valvula MitraHs.) Its margin is secured from being pushed 
into the left auricle by numerous chordae tendineoa, which are at- 
tached by their other extremities to four or five columnar carnese pro- 
jecting from the surface of the ventricle. The whole internal ar- 
rangement of this cavity indicates a great increase of strength over 
that of the right side : in the robustness of its fleshy columns ; the 
number and size of its tendinous chords ; and the greater thickness 
of its valve. The upper division of the mitral valve is placed im- 
mediately below the orifice of the aorta, and is considerably broader 
than the other, so that when it opens to admit blood, it is in some 
measure thrown over the aortic orifice. There is less of an inter- 
texture among the tendinous chords here than on the right side of 
the heart: they cluster more, and, owing to the breadth of the ex- 
tremities of the fleshy columns, are more parallel. 

The Septum of the Ventricles is of considerable thickness, being 
formed almost exclusively by the continuation of the fibres of the 
reft ventricle. Where the large columnee carnese elevate themselves 
on its surface, its thickness is increased. Its shape is somewhat 
triangular. It forms a round projection into the right ventricle, 
while its other surface, which presents to the left, is concave to the 
same degree. It is rather thinner as it approaches the auricular 
septum than elsewhere. Its fibres near the apex are less closely 
connected to each other. 



THE HEART. 



227 



The orifice of the Aorta is furnished with three Semi-lunar Valves,* 
which, in the mode of their arrangement, correspond precisely with 
those of the pulmonary artery. They are, however, thicker, and 
the Corpuscula Aurantii are larger. The Sinuses of Valsalva, at- 
tended with a slight dilatation of the artery, exist in the same way- 
Just beyond the margin of the right and of the left valve, are ob- 
served the orifices of the two coronary arteries. The orifice of the 
aorta is somewhat tendinous, which marks out the distinction of 
structure between it and the ventricle. 



Of the Texture of the Heart. 

The Heart, with the exception of the serous membrane which 
lines its cavities, called the Endocardium, and of the serous lamina 
of pericardium which covers its surface, consists almost entirely of 
muscular fibres. 

The sides of the auricles, as stated, are much thinner than those 
of the ventricles. In the right auricle, the stratum of muscular fibres 
is uniform in its venous portion, but on the sinus is arranged into 
the parallel fasciculi called the Musculi Pectinati ; a circular fasci- 
culus surrounds the orifice of the descending cava. In the left 
auricle, the stratum of muscular fibres forms a uniform layer, and is 
also thicker than on the right side. These fasciculi commence on 
the pulmonary veins and run transversely across the auricle, with 
the exception of the more deeply seated, which are irregular, and 
crossed upon each other. The septum of the auricles is also formed 
by a muscular stratum. 

* Mr. Erslune Hazard has furnished me with the following estimate on the 
action of these valves r — 

If the diameter of the artery be put = 10, the 
length of the superior edge of the valve will also 
be 10. The arc occupied by the valve will be 
10.47 = 120° of the circle. The valves, when 
open, will either assume the form at B, or that of 
the double chord of GO , as at A. In either case, 
being .17 shorter than the arc, they cannot come 
in contact with it, and must, therefore, leave room 
for the blood to get behind them, and depress the 
valves. For the same reason, they cannot close 
the orifice of the coronary arteries. The chord of 
120° would be 8.G7. 



Fi ff . 38. 




228 



CIRCULATORY SYSTEM. 



In the ventricles, the superficial fasciculi observe a spiral course, 
and many of those belonging to the left ventricle may be traced 
over the right ; as the fibres are more deeply situated, they become 
shorter and more interwoven. In the septum, between the ven- 
tricles, the fibres of the two cavities are much interlocked ; but with 
some trouble may be partially separated. The fibres of the colum- 
nse carneae are too irregular in their course, to admit even of a gene- 
ral description. It would appear, however, that they are a conti- 
nuation of the superficial spiral fibres of the ventricles which penetrate 
into the interior of the heart at its apex, and leave there a small 
foramen which is closed only by the pericardium externally, and the 
lining membrane of the heart. M. Gerdy asserts, that all the fibres 
of the heart arise from, and are inserted into, the tendinous rings 
forming the ostia venosa and the orifices of the large arteries ; having 
m the mean time traversed the course which is peculiar to the several 
fasciculi, accordingto their being superficial, in the middle, or deep- 
seated.* 

All the cavities of the heart are lined by a serous membrane 
{Endocardium) resembling that of the blood vessels. It is the du- 
plicature of this with some intermediate fibrous tissue, which in each 
case makes the valves, the thickness of which is proportionate to 
requirements of the circulation. 

Of the Blood Vessels of the Heart. 

The Heart is furnished with both arteries and veins, which bel< 
to its nutritious system. 

The Arteries called Coronary, arise, as observed, from the trunk 
of the aorta, somewhat above the margins of the semi-lunar valves; 
so that when the latter are applied against the aorta, the orifices of 
these arteries are still visible. 

The Right Coronary Artery begins above the anterior valve, and 
passes to the right, beneath the pulmonary artery; it then shows 
itself in the upper part of the fissure, between the right auricle and 
right ventricle, and follows the course of this fissure to the flat side 
of the heart. It detaches, as it goes along, several small branches; 

* For a very detailed exposition of the structure of the Heart, see Wolff 
Act. Acad. Petrop. 1781 ; and Gerdy, Journal Complementaire du Diet. des. 
Sc. Med. vol. x. p. 97. 



VESSELS OF THE HEART. 229 

which come off at right angles from it. One set of these branches 
is distributed upon the right ventricle, and another set upon the 
right auricle. Small branches are also sent from it to the root of 
the pulmonary artery, and to that of the aorta. 

The Left Coronary Artery begins above the left semi-lunar valve. 
While its root is still obscured by the pulmonary artery, it divides 
into two principal branches, of which the anterior runs in the fissure 
on the upper part of the septum of the ventricles to the apex of the 
heart, and in this course distributes branches to the right and left 
ventricle : those to the right anastomose with the branches of the 
right coronary artery, which go to the same ventricle. The other 
branch goes along the groove, on the septum, between the left au- 
ricle and left ventricle, and reaches the under surface of the heart; 
and in this course distributes many branches to the left auricle and 
left ventricle, both on their upper and under surfaces. It anasto- 
moses freely with the branches of the trunk that run along the upper 
part of the septum. 

In consequence of the frequency of the anastomoses between the 
two coronary arteries, injecting matter thrown into one very readily 
finds its way into the other. 

The Coronary Veins receive the blood, which is distributed by 
the coronary arteries through the substance of the heart. 

The Great Coronary Vein ( Vena Coronaria Maxima Cordis) is 
formed by the union of several trunks, which run from the apex 
towards the base of the heart. One of them begins at the apex, 
goes along the superior fissure of the septum of the ventricles, and 
then winds to the left side, between the left auricle, and the left 
ventricle : while in the latter position, it is joined by several trunks 
coming from the left ventricle and the left auricle : it, finally, emp- 
ties into the lower part of the right auricle, just in front, as men- 
tioned, of the orifice of the ascending cava; being there covered by 
its own valve. 

The Lesser Coronary Vein (Vena Coron. Minor Cordis) lies in 
the inferior fissure of the septum of the ventricles. It begins at the 
apex, and, going backwards, collects the blood from the flat surface 



230 CIRCULATORY SYSTEM. 

of the heart, principally on the right ventricle. It discharges into 
the great coronary vein, just before the latter terminates in the au- 
ricle. 

Besides the preceding veins, some of a smaller size exist on the 
right ventricle and auricle, and about the root of the aorta and pul- 
monary artery, and empty by several orifices into the right auricle. 
There are also some veins of a still smaller size, which open into 
all the cavities of the heart by little orifices, called the Foramina of 
Thebesius: by Mr. Abernethy they are considered as being larger 
when the lungs are diseased.* 

The Nerves of the Heart come principally from the cervical 
ganglions of the sympathetic, and follow the course of the coronary 
arteries. It has been doubted whether these nerves are actually 
distributed in the substance of the heart, from the presumption, that 
as they cannot be traced beyond the third order of branches of the 
coronary arteries, they are limited to them. But, as the ramifica- 
tions of the sympathetic are bestowed exclusively upon the branches 
of the circulatory system, Meckel has very properly suggested, that 
the heart being also supplied with nerves from the same source, it 
follows that there can be no departure from the general rule, as the 
heart is nothing more than the fibrous portion of the blood vessels 
more completely developed. 

While the circulation continues, as both auricles contract at the 
same instant, whereby the blood is thrown into the ventricles, and 
as immediately afterwards the ventricles contract simultaneously 
also ; whereby the blood is forced into the aorta and the pulmonary 
artery, so it is the contraction of the ventricles which causes the 
heart to strike against the parietes of the thorax. For, as was first 
pointed out by Dr. W. Hunter, the blood which is forced through 
the large arteries, by extending them diminishes their curvature, or 
brings them more into a straight line, in which effort the heart 
bounds up from the tendinous centre of the diaphragm. The filling 
of the auricles, while this is going on, also assists in protruding the 
heart forwards. The French anatomists assert, that during the con- 
traction of the ventricles, their extremity is elevated or bent up- 
wards on the body of the heart, which will also increase the mo- 
mentum of the stroke against the thorax. 

* London Philosophical Transactions, 1798. 



BRANCHES FROM THE ARCH OF THE AORTA. 231 



CHAPTER II. 
Of the Arteries. 

SECT. I. — THE AORTA AND THE BRANCHES FROM ITS 
CURVATURE. 

The Aorta is the trunk of the arterial system. Having arisen from 
the superior posterior end of the left ventricle, its root passes be- 
neath the pulmonary artery, and is entirely concealed in front by it. 
Keeping to the right it emerges at the base of the heart, between the 
right auricle and the trunk of the pulmonary artery, being bounded on 
the right side by the descending cava. Continuing its ascent it forms 
a curvature with the convexity upwards, and the summit of which 
rises to within eight or twelve lines of the superior edge of the 
sternum. This curvature is in front of the third and fourth dorsal 
vertebrae, and its direction is nearly marked out by a line drawn 
from the anterior extremity of the third right rib, to the posterior 
end or tubercle of the third one on the left side. In this course, 
therefore, the aorta passes over the right pulmonary artery, across 
the left bronchus, and applies itself to the left side of the spine, about 
the third or fourth dorsal vertebra. It is this curvature which ob- 
tains the name of the Arch of the Aorta, (Arcus Aorta.) 

Near its origin, where the aorta is still within the pericardium, 
it has very commonly, especially in persons advanced in age, a di- 
latation, which is called the Great Sinus to distinguish it from the 
lesser sinuses, or those of Valsalva. This dilatation is useful in 
diminishing the resistance arising from the curvature of the aorta, to 
the current of blood ; or rather it is a provision for doing away with 
the effects of friction, as by it a larger current of blood becomes a 
compensation for diminished velocity. The ascending portion of 
the arch is to the right of the vertebral column, the descending por- 
tion to the left, and the middle or horizontal part goes in front of the 
trachea. 



232 CIRCULATORY SYSTEM. 

The aorta, in its descent down the thorax, is placed in the pos- 
terior mediastinum, and is covered on one of its sides, by the left 
pleura, while the other side is in contact with the left surface of the 
bodies of the dorsal vertebrae. At the lower part of the thorax it in- 
clines towards the middle line of the vertebrae, in order to reach the 
hiatus aorticus of the diaphragm, through which it penetrates to the 
abdomen. In the abdomen it descends in front of the lumbar ver- 
tebras, somewhat on their left side ; and at the intervertebral space 
between the fourth and fifth vertebras of the loins, or somewhat above, 
it ceases, by being divided into two large trunks, the Primitive 
Iliacs ; one for each lower extremity, and the corresponding side of 
the pelvis. 

In this course of the aorta, from the heart to the loins, it first gives 
off the branches which supply the head and the superior extremities ; 
then, those which supply the sides of the thorax: afterwards in the 
abdomen, it detaches the trunks which supply the viscera and the 
sides of the latter cavity. 

The Coronary Arteries are, strictly speaking, the first branches of 
the aorta, but as they belong especially to the heart, their descrip- 
tion is associated- with it. In all the space between them and the 
superior convexity of the aortic arch no branches are given off; but 
as the aorta is crossing the trachea three considerable trunks arise 
from it, which are distributed upon the head and the upper extremi- 
ties principally. They are, the Arteria Innominata, the Left Primi- 
tive Carotid, and the Left Subclavian. 

The Jlrteria Innominata is first in its origin : in ascending from 
left to right in front of the trachea, and behind the Transverse vein, 
it crosses the trachea very obliquely ; is from an inch to an inch and a 
half, and sometimes, though rarely, two inches long, when it divides 
into the right subclavian and the right primitive carotid. The left 
primitive carotid arises from the aorta, close upon the left border of 
the innominata ; frequently, indeed, from a part of it. The left sub- 
clavian artery, at its origin near the left carotid, generally leaves a 
distinct interval of one, two, or three lines. The relative situation 
of these trunks is particularly alluded to in the account of the supe- 
rior mediastinum. The last two are, of course, longer than the 
corresponding trunks of the right side, by the whole length of the 
arteria innominata. With the exceptions connected with their mode 



BRANCHES FROM THE ARCH OF THE AORTA. 233 

of origin, the arterial trunks of the two sides are exactly alike, and 
have the same mode of distribution. 

The Common Carotid Artery (Carotis Primitiva) being a branch 
of the innominata on the right side, and of the aorta on the left, goes 
up the neck to terminate just below the cornu of the os hyoides. In 
the early part of its course, the right one is more inclined outwardly 
than the left, owing to its origin from the arteria innominata in front 
of, and to the right side of the trachea ; whereas, the left ascends 
almost vertically. 

At the lower part of the neck, just above the sternum and the 
clavicle, the carotid is covered by the sterno-hyoid and thyroid 
muscles, and by the sternal portion of the sterno-cleido-mastoid. 
It is crossed obliquely on a line with the lower part of the thyroid 
cartilage of the larynx, by the omo-hyoid muscle. It lies at the side 
of the thyroid gland, the trachea, the larynx, the oesophagus, and 
pharynx, in front of the transverse processes of the cervical vertebrae, 
and the longus colli muscle ; having on its outer margin, but some- 
what in front, the internal jugular vein, and the pneumogastric nerve 
enclosed in the same sheath, and the sympathetic nerve behind. At 
the side of the larynx, the carotid is very superficial, and with the 
exception of being crossed by the omo-hyoideus muscle, it is only 
covered by the platysma myodes and the integuments. 

The Carotid having got as high as the space between the os 
hyoides and the thyroid cartilage, but varying slightly in different 
subjects, there divides into two large trunks, the Internal Carotid, 
which goes to the brain and to the eye : and the External Carotid, 
which is principally distributed upon the more superficial parts of 
the head and neck. The first of these trunks is placed behind the 
other, and bends outwardly at its root : it is generally the largest in 
infancy, on account of the proportionate volume of the brain at that 
age ; it is also swollen at its root, so as to form a sinus there, re- 
sembling an incipient aneurism. No branch, except in the abnor- 
mous cases, is given off from the common carotid between its origin 
and bifurcation. 



Vol. II.— 21 



234 CIRCULATORY SYSTEM. 



SECT. II. — OF THE CAROTIDS, AND THEIR BRANCHES.* 

The Internal Carotid, (Arteria Carotis Interna,) in the adult, is 
smaller than the external, and extends from the larynx to the sella 
turcica. It ascends between the external corotid and the vertebrae of 
the neck, being in front of the internal jugular vein, and having the 
pneumogastric nerve at its outer margin : as it gets on a level with 
the base of the lower jaw, it is crossed externally by the digastric and 
the stylo-hyoid muscles ; it is immediately afterwards concealed in the 
subsequent part of its ascent by the ramus of the lower jaw. Having 
gone along the most internal or deeply seated margin of the parotid 
gland and of the styloid process of the temporal bone, at the side 
of the superior constrictor of the pharynx, it then penetrates into the 
cranium through the carotid canal of the temporal bone. 

It is slightly flexed between its origin and the carotid canal : just 
before it reaches the latter, it curves upwards and forwards. The 
first part of its course through the canal is vertical, afterwards it goes 
horizontally forwards ; and to escape from the canal it has once more 
to ascend almost vertically, which brings it to the posterior extre- 
mity of the Sella Turcica. On the side of the Sella Turcica it again 
passes horizontally forwards through the cavernous sinus ; and at 
the anterior clinoid process it once more ascends, and, having pene- 
trated the dura mater, it reaches the brain. 

In this passage, through the carotid canal, it is attended by the 
upper extremity of the sympathetic nerve, and gives one or more 
small branches to the petrous bone ; it also gives a few branches to 
the dura mater and to the nerves about the cavernous sinus. But, 
for the full exposition of the distribution of the internal carotid, see 
the arteries of the Brain and of the Eye. 

The External Carotid Artery {Art. Carotis Externa) extends from 
the termination of the primitive carotid, to the neck of the lower jaw. 
In the early part of its course, where it is situated in front of the in- 
ternal carotid, and between the pharynx and the sterno-mastoid 
muscle, it is comparatively superficial, being only enveloped by its 
sheath, and covered by the platysma myodes and the skin. Just 
above this place it is crossed externally by the hypoglossal nerve, 

* Anat. Atlas, Figs. 448 to 453 inclusive. 



CAROTIDS, AND THEIR BRANCHES. 235 

which detaches the descending branch along the front of its sheath 
and of that of the primitive carotid. Somewhat above this nerve, 
it is also crossed externally by the digastric and the stylo-hyoid 
muscle, and lies there on the side of the superior constrictor muscle 
of the pharynx, near the tonsil gland. About its middle, it is 
crossed internally by the stylo-glossus and the stylo-pharyngeus 
muscle ; it then ascends through the substance of the parotid 
gland, between the ramus of the lower jaw and the ear, to its ter- 
mination. 

Several very important branches are given off from the external 
carotid ; they are as follow : 

The Superior Thyroid Artery (Art. Thyroidea Superior) arises 
from the external carotid, about a line above its root, and is distri- 
buted to the larynx and to the thyroid gland. It goes at first inwards 
and forwards on the side of the larynx, being covered by the omo- 
hyoideus muscle, and by the platysma myodes ; it then descends 
under the sterno-thyroideus to the upper margin of the lobe of the 
thyroid gland. In this course it performs several flexuosities, of con- 
siderable variety in different individuals. 

The Laryngeal Branch comes from it near the superior margin of 
the thyroid cartilage ; this branch glides in between the thyro-hyoid 
muscle and the middle thyro-hyoid membrane or ligament ; after a 
short course, it penetrates the latter, and is then distributed in a great 
number of small twigs to the muscles and to the lining membrane 
of the larynx. A small trunk, either from the laryngeal branch, or 
from the thyroid artery itself, is spent upon the crico-thyroid muscle, 
and traversing the front surface of the middle crico-thyroid ligament, 
anastomoses with its fellow : small twigs from this branch penetrate 
to the interior of the larynx through the middle crico-thyroid liga- 
ment. Sometimes this crico-thyroid ramus is superior in size to the 
one above, in which case it principally supplies the interior of the 
larynx. 

The Thyroid Branch is the continuation of the principal trunk : it 
penetrates into the substance of the thyroid gland, and divides into 
two ramuscules, one of which goes along the posterior face of the 
lobe of the gland, and anastomoses with the inferior thyroid ; the 
other goes along the upper margin of the gland, and anastomoses 
with its congener of the opposite side. The thyroidal artery is split 
Up into a great many branches in the substance of the gland, it also 



236 CIRCULATORY SYSTEM. 

sends small branches to the pharynx, oesophagus, and the little mus- 
cles on the front of the neck. 

The Lingual Artery {Art. Lingualis) comes from the external 
carotid at the distance of from six to twelve lines above the superior 
thyroid, and goes to the tongue. It is concealed in the early part 
of its course by the digastric and the stylo-hyoid muscles ; it then 
penetrates the hyo-glossus muscle just above the cornu of the os 
hyoides, or goes between it and the middle constrictor of the pharynx ; 
it then ascends between the hyo-glossus and the genio -hyo-glossus 
muscle ; advancing forwards, it is placed between the latter and the 
sublingual gland, and, finally, reaches the tip of the tongue. 

The lingual artery sends off the following branches. At the root 
of the tongue one or more trunks arise from it, the Dorsales Lingua 
which go to the base of this organ, the tonsils, the palate, and the 
epiglottis ; one of these branches is called the Inferior palatine. A 
little farther on, the lingual detaches another branch, the Ramus Sub- 
lingualis, which, advancing between the mylo-hyoid and the genio- 
hyo-glossus muscle, and above the sublingual gland, sends a great 
many ramifications to these parts and to the lining membrane of the 
mouth ; it is sometimes a branch of the facial. The Ramus Raninus, 
is the continuation of the lingual ; it advances between the lingualis 
and the genio-hyo-glossus muscle, to the tip of the tongue, distri- 
buting continually its twigs on each margin, and ends there by anas- 
tomosing with the corresponding artery of the other side. 

The Facial Artery {Arteria Facialis, Maxillaris Externa) arises 
from the external carotid two or three lines above the lingual, and 
is spent principally on the side of the face below the eye. It is of 
considerable size, and very tortuous; its root is concealed by the 
stylo-hyoid and the digastric muscle, and it is traversed externally 
by the hypo-glossal nerve. It goes forward within theangle of the 
lower jaw, and above the submaxillary gland, but very much con- 
nected with it : it then mounts over the base of the maxilla inferior, 
at the anterior margin of the masseter muscle, and afterwards shapes 
its course, in a serpentine manner, to the internal canthus of the eye, 
passing between the muscles and the integuments of the face. In 
this course, the facial artery sends off the following branches: 

As it passes by the submaxillary gland it sends several twigs to 
it : previously it also sends several little branches to the contiguous 



CAROTIDS, AND THEIR BRANCHES. 237 

muscles, as the internal pterygoid, digastric, and so on ; but they 
are too small to be of much consequence. 

The Submental branch arises, then, on a level with the base of the 
lower jaw ; it advances forwards under the origin of the mylo-hy- 
oideus, and above the anterior belly of the digastricus. It sends 
several branches to these muscles, some of which anastomose with 
the ranine artery; behind the symphysis of the jaw it anastomoses 
with its fellow, it then mounts over the chin, to which and to the 
lower lip it is distributed, anastomosing there with the inferior coro- 
nary artery of the mouth, and with the inferior maxillary which 
comes out from the anterior mental foramen in the lower jaw. 

When the facial artery has got upon the face, it sends backwards 
a small branch to the lower part of the masseter muscle. Somewhat 
above this it sends forwards a branch called the Inferior Labial, 
which is distributed upon the middle of the chin. When it gets on 
a level with the corner of the mouth, but sometimes lower down, it 
sends forward, under the depressor anguli oris, the Inferior Coronary 
Artery, to the lower lip, which frequently supplies the place of the 
inferior labial entirely ; but when the latter is large, the coronary is 
small in proportion : a few lines higher up the facial sends forward 
a third branch, the Superior Coronary, which goes to the upper lip. 
These coronary arteries are very tortuous, and are distributed by 
many branches in the substance of the lips : by anastomosing with 
their congeners of the other side, they surround the mouth com- 
pletely. The superior coronary artery, as it passes under the nose, 
sends upwards one or more small branches to the integuments of its 
orifice and septum. 

After this, the facial artery, in ascending towards the internal 
canthus of the eye, sends a branch to the ala nasi, and another to 
anastomose with the infra-orbitar artery. It, finally terminates at 
the internal canthus of the eye by anastomosing with the branches 
of the ophthalmic, which come out there upon the side of the root 
of the nose. Several ramuscules, which are too small to merit spe- 
cial description, are given by the facial to the integuments and mus- 
cles of the face, and to the lower eyelid. 

The Inferior Pharyngeal Artery {Art. Pharyngea Inferior, ascen- 
dens) is one of the smallest of the original branches of the external 
carotid, and generally arises opposite to the lingual ; but there is. 
much variety in the latter respect, it being sometimes higher up or 

21* 



238 CIRCULATORY SYSTEM. 

lower down, and not unfrequently a branch of one of the other arte- 
ries, instead of being an original trunk. It ascends on the side of 
the pharynx, between the external and the internal carotid, and is 
covered by the stylo-pharyngeus muscle. It is principally distri- 
buted on the constrictor muscles of the pharynx, and upon their 
lining membrane. But one of its branches, called the Posterior 
Meningeal Artery, ascends through the posterior foramen lacerum 
of the cranium, between the jugular vein and the pneumo-gastric 
nerve, and is distributed on the contiguous dura mater. 

The Occipital Artery (Arteria Occipitalis) is a very considerable 
trunk, which comes from the external carotid, generally opposite to 
the facial, and is spent upon the integuments, on the back part of the 
head. 

At its root, it is deeply situated in the side of the neck, below the 
parotid gland, and has the internal jugular vein and the par vagum 
on its inside. It goes obliquely backwards, in ascending along the 
posterior belly of the digastricus between the transverse process of 
the atlas and the mastoid portion of the temporal bone, and is be- 
neath the several muscles which are inserted into the latter, as the 
sterno-mastoid, the splenius, and the trachelo-mastoid. It is covered, 
for some distance, by the insertion of the splenius capitis, and be- 
comes at length superficial at the posterior margin of this muscle. 
The occipital artery is distributed as follows : 

Shortly after its origin, it sends branches to the digastric muscle 
behind, to the upper part of the sterno-mastoid and to the lymphatic 
glands of the upper part of the neck. While enclosed by the mus- 
cles on the back of the neck, it also sends branches to them, and 
anastomoses thereby with the vertebral artery ; occasionally, one of 
these branches is of considerable magnitude, and has been found de- 
scending very low on the back, between the splenius and the corn- 
plexus muscle. It also sends a small branch to the dura mater, through 
the mastoid foramen generally, but sometimes through the posterior 
foramen lacerum. When the -stylo-mastoid artery is wanting, it also 
detaches a branch through the stylo-mastoid foramen to the internal 
parts of the ear. 

The occipital artery, having become superficial at the internal 
margin of the splenius on the occiput, ascends on the latter bone 
towards the vertex in a tortuous manner, sending off, on each side, 



CAROTIDS, AND THEIR BRANCHES. 239 

many small ramifications. It ends by anastomosing with the pos- 
terior temporal artery. 

The Posterior Auricular Artery (Art. Auricularis Posterior) arises 
a little above the last, at the lower edge of the parotid gland, from 
the external carotid, and is one of its smallest branches. It ascends 
backwards enclosed by the parotid gland, and afterwards between 
the meatus auditorius externus and the mastoid bone: at the latter 
place, it sends a ramification to the internal side of the external 
ear; it then ascends and is distributed, by small branches, on the 
contiguous integuments of the side of the head. While still in- 
volved in the parotid gland, it sends some small ramifications 
through the meatus externus to its lining membrane and the mem- 
brana tympani. It then detaches a branch through the stylo-mastoid 
foramen, from which the whole artery is also named Stylo-Mastoid ; 
but this branch, as stated, sometimes comes from the occipital. 
The stylo-mastoid passes along the aqueduct of Fallopius, detaching 
its arterioles to the tympanum and to the labyrinth. 

The External Carotid having given off these trunks, penetrates 
vertically through the inner margin of the parotid gland, and gives 
to it several small twigs. When it arrives on a line with the neck 
of the lower jaw, it divides into two large trunks; one of them, the 
Internal Maxillary, goes to the parts within the ramus of the lower 
jaw ; the other, being smaller, is the Temporal Artery. 

The Temporal Artery (Arteria Temporalis) continues to ascend 
through the substance of the parotid, but becomes superficial in 
front of the meatus externus, in mounting over the root of the 
zygoma ; it is then distributed to the integuments on the side of the 
head. It frequently sends off one or two ramifications, of but little 
volume, to the masseter muscle. Just above its root, and while 
surrounded by the parotid, a branch of some importance, the Trans- 
verse Facial, (Transversalis Faciei,) leaves it, and crosses, horizon- 
tally, the masseter muscle, just below the parotid duct, sometimes 
above it. This branch is distributed to the adjacent integuments 
and muscles, and terminates in front by anastomosing with the facial 
and the infra-orbitar artery. 

A little below the zygoma, the Middle Temporal artery (Art. 
Temp. Media) comes off from the Temporal, and ascending with the 
parent trunk, perforates the temporal fascia at the upper margin of 



240 CIRCULATORY SYSTEM. 

the zygoma, and is distributed to the temporal muscle by many 
ramifications, which anastomose with the deep-seated temporal arte- 
ries. After this, some small twigs, called Auricular, go to the ex- 
ternal ear from the trunk of the temporal artery. 

The temporal artery, having ascended for an inch or so between 
the aponeurosis of the temporal muscle and the skin, it divides into 
an Anterior and a Posterior Branch. The former ascends towards 
the side of the os frontis, and is distributed in ramuscules to the orbi- 
cularis palpebrarum, the anterior belly of the occipito frontalis, and 
the integuments of the front of the cranium, anastomosing' with the 
frontal artery and the temporal of the other side. The posterior 
branch is distributed on the integuments of the middle of the side of 
the cranium, anastomosing with the anterior branch, with its fellow 
of the other side, and with the occipital artery. 

The Internal Maxillary Artery [Arteria Maxillaris Interna) winds 
round the neck of the lower jaw, and, passing between the ptery- 
goid muscles, proceeds in a tortuous manner to the deepest points 
of the zygomatic fossa. The first part of its course is horizontally 
inwards ; it then ascends in front of the pterygoideus externus to 
the bottom of the temporal bone, or the spinous process of the sphe- 
noidal : it then passes forwards, within the temporal muscle, to the 
upper part of the pterygo-maxillary fossa. 

It sends off several branches, and commonly in the following 
order : — 

1. The Arteria Tympanica, to the tympanum, through the glenoid 
fissure. 

2. The Arteria Meningea Parva, to the dura mater, through the 
foramen ovale. It is most frequently a branch of the next. 

3. The Arteria Meningea Magna, or Media, to the dura mater, 
through the foramen spinale. This branch having entered the cra- 
nium, is distributed upon the dura mater in the manner marked off 
by the furrows upon the internal face of the temporal, the parietal, 
and the frontal bones. One of its branches enters the aqueduct of 
Fallopius, through the Vidian Foramen, and is distributed upon the 
internal parts of the organ of hearing, anastomosing with the stylo- 
mastoid artery. 



CAROTIDS, AND THEIR BRANCHES. 241 

4. The Arteria Maxillaris, or Dentalis Inferior, descends along 
the internal face of the ramus of the lower jaw, and having sent off 
some ramifications of small size to the contiguous muscles and the 
lining membrane of the mouth, it enters the posterior mental foramen 
with the inferior dental nerve. Going along the canal in the sub- 
stance of the lower jaw, it detaches successively from its superior 
margin ramifications to the teeth. At the anterior mental foramen 
a trunk is sent forward as far as the symphysis, which supplies in 
its course the canine and incisor teeth ; the remainder of the inferior 
maxillary artery comes out at the foramen, and supplies the chin, 
anastomosing with the facial artery. 

5. The ArterisB Temporales Profunda? are two in number. The 
first of them, called Posterior, arises next to the inferior maxillary. 
It is concealed between the external pterygoid and the temporal 
muscle for some distance ; it then ascends in the posterior part of the 
temporal fossa, beneath the temporal muscle, and is minutely distri- 
buted upon it. The Anterior deep temporal artery is separated from 
the posterior, in its origin from the external maxillary, by the ptery- 
goid and the buccal arteries. It arises near the pterygo-maxillary 
fossa; and, ascending between the temporal muscle and the fore 
part of the corresponding fossa, it is minutely distributed upon the 
former, anastomosing with the posterior deep, and with the middle 
temporal artery. 

6. The Arteria? Pterygoidese arise after the posterior deep tem- 
poral. They vary considerably in regard to number, size, and origin, 
and are distributed upon the pterygoid muscles, as their name implies. 
One of their branches, which is sometimes an independent trunk from 
the internal maxillary, goes between the posterior margin of the tem- 
poral muscle and of the neck of the lower jaw, in front of the latter, 
to be distributed upon the internal face of the masseter muscle. 

7. The Arteria Buccalis, sometimes a branch of the internal 
maxillary, but frequently coming from one of its trunks, either the 
alveolar or the anterior temporal, passes along the external face of 
the upper jaw, and distributes its branches to the buccinator and 
zygomatic muscles, and to the lining membrane of the mouth. 

8. The Arteria Maxillaris Superior, or Alveolaris, proceeds down- 



242 CIRCULATORY SYSTEM. 

wards and forwards in winding round the tuber of the upper jaw 
bone. It first sends some ramifications through the bone to the roots 
of the great and small molar teeth, and to the lining membrane of 
the maxillary sinus ; it then passes forwards along the gums, near 
the buccinator, and gives ramifications to them and to the contiguous 
muscles. 

9. The Arteria Infra-orbitalis comes from the internal maxillary, 
at the upper part of the pterygo-maxillary fossa ; it sends some in- 
considerable ramifications to the fat and the periosteum of the orbit, 
through the spheno-maxillary fissure. It then enters the infra-orbi- 
tary canal, and passes through it with the infra-orbitary nerve. On 
arriving near the anterior orifice of the canal, it detaches downwards 
a branch which goes to the canine and the incisor teeth, and to the 
lining membrane of the antrum. It then gets to the face below the 
origin of the levator labii superioris muscle, and is distributed upon 
the muscles in front of the upper maxilla, anastomosing with the 
facial and with the ophthalmic artery. 

10. The Arteria Palatina Superior descends through the posterior 
palatine canal, and having reached the mouth, leaves some ramifica- 
tions with the soft palate : it then advances between the bones and 
the lining membrane of the roof of the mouth, and disperses itself in 
several small twigs; one of which passes through the foramen in- 
cisivum into the nostril. 

11. The Arteria Pharyngea Superior is sometimes a branch of the 
last, and is spent upon that portion of the pharynx bordering on the 
pterygoid processes. 

12. The Arteria Spheno-Palatina is the terminating trunk of the 
internal maxillary : it enters the nose through the spheno-palatine 
foramen, and divides into two branches, which are minutely dis- 
tributed over the Schneiderian membrane. One of them descends 
along the septum narium ; the other along the external margin of the 
posterior naris, and divides into two principal ramuscules, one of 
which is dispersed along the middle turbinated, and the other along 
the inferior turbinated bone. 



SUBCLAVIAN, AND ITS BRANCHES. 243 



SECT. III. — OF THE SUBCLAVIAN ARTERY, AND ITS 
BRANCHES.* 

The Subclavian Artery (Arteria Subclavia) of the right side 
having arisen from the innominata, and that of the left from the 
aorta, they each go over the first rib of their respective sides, ad- 
hering closely to it, in the bottom of the interval between the sca- 
lenus anticus and medius muscle. The right subclavian is much 
shorter, and more superficial than the left, from its origin to the 
scaleni muscles. Near the latter they are each covered in front by 
the sternal end of the clavicle, by the sterno-hyoid and thyroid 
muscle, and by the subclavian vein of the corresponding side ; be- 
hind they are separated from the vertebral column by the longus 
colli muscle ; below them is the pleura, the left artery being in con- 
tact with it for its whole passage in the thorax ; and on their internal 
side is the primitive carotid. The subclavian of the right side 
is crossed near the scalenus anticus by the par vagum ; the 
phrenic nerve also goes in front of it, but on the internal edge of 
the scalenus. The subclavian of the left side having a course almost 
vertical from its origin to the interval of the scaleni muscles, is nearly 
parallel with and behind the primitive carotid of that side ; the 
phrenic nerve has the same relative position with it as on the right 
side ; but the par vagum goes parallel with, and in front of the sub- 
clavian artery, for some distance along the root of the latter. 

At the inner margin of the Scaleni Muscles the Subclavian gives 
off a cluster of trunks ; to wit, the Vertebral ; the Inferior Thyroid ; 
the Superior Intercostal ; the Internal Mammary ; and the Posterior 
Cervical Artery. They sometimes arise distinctly, and after the 
order mentioned : but there is too great a diversity in subjects to 
establish any rule on these points. 

1. The Vertebral Artery [Arteria Vertebralis) is the most volu- 
minous of the branches of the Subclavian. Immediately after its 
origin it ascends on the side of the spine, and enters the canal of the 
transverse processes of the neck at the sixth vertebra. Pursuing 
this course, it gets into the cavity of the cranium through the fora- 
men magnum occipitis, and is distributed to the brain in the manner 
mentioned in the description of that organ. 

* Anat. Atlas, Figs. 454 to 460 inclusive. 



244 CIRCULATORY SYSTEM. 

While in the canal of the transverse processes, it sends off 
several branches to the heads of the contiguous muscles, and to the 
medulla spinalis of the neck. The vertebral artery, like some 
others, is spindle-shaped, its size augmenting as it recedes from 
its origin; this imparts some advantage to the current of the 
blood. 

2. The Inferior Thyroid Artery (Arteria Thyroidea Inferior) arises 
from the upper face of the subclavian, and goes to the thyroid gland. 
It ascends at first on the internal margin of the scalenus medius 
muscle, and then turns suddenly inwards between the vertebrae and 
the great vessels of the neck. 

In this course several unimportant twigs are sent from it to the 
contiguous parts. Near its root it detaches the Anterior, or the 
.Ascending Cervical Artery, which going up the neck is spent upon 
the heads of the muscles arising from the transverse processes, as 
the scaleni, the longus colli, and so on. The inferior thyroidal 
then gets to the thyroid gland, and is very minutely distributed to 
it, anastomosing with the other arteries which supply the same 
organ. 

3. The Superior Intercostal Artery, [Arteria Intercostalis Supeiior,) 
arising from the under surface of the subclavian opposite the inferior 
thyroid, descends across the neck of the first rib, and divides into 
two branches, which supply the two upper intercostal spaces : each 
of them also sends backwards near the vertebra a small trunk to the 
muscles of the back. 

4. The Internal Mammary Artery (Arteria Mammaria Interna, 
Thoracica) descends at first along the internal margin of the scalenus 
anticus; having then got fairly into the cavity of the thorax, it con- 
tinues to descend across the posterior face of the costal cartilages, 
parallel with, and about nine lines from the outer edge of the sternum, 
between the triangularis sterni and the intercostal muscles. 

In this course, besides some distinct twigs to the anterior medi- 
astinum, it sends a branch (Phrenica Superior) which accompanying 
the phrenic nerve between the pleura and the pericardium, reaches 
finally the diaphragm, and is spent upon it. At each intercostal 
space which it crosses, the internal mammary sends outwards a 
branch, which is spent upon the fore part of the intercostal muscles, 



SUBCLAVIAN, AND ITS BRANCHES. 245 

and anastomoses with the corresponding intercostal artery: other 
branches also leave it at each space, which getting forwards near 
the sternum, are distributed upon the pectoralis major, and upon 
the contiguous muscles. The last of these branches, according to 
M. H. Cloquet, goes transversely across the ensiform cartilage, and, 
having anastomosed with its fellow, descends between the peritoneum 
and the linea alba to the suspensory ligament of the liver. 

On a level generally with the anterior extremity of the sixth rib, 
the internal mammary divides into two principal branches; the most 
exterior of which, descending along the cartilaginous margin of the 
thorax, is distributed in small twigs to the origin there of the dia- 
phragm and of the transverse muscle of the abdomen. The internal 
branch reaches the posterior face of the rectus abdominis muscle, 
and is dispersed upon it: some of its branches go as low as the 
umbilicus, to anastomose there with the epigastric artery. 

5. The Posterior Cervical Artery [Arteria Cervicalis Posterior, 
Transversa) is of a very unsettled origin, but comes most frequently, 
either from the subclavian itself, or from the inferior thyroid. It is 
but small in some subjects, owing to its place being supplied by 
branches from the adjoining arteries. 

It crosses horizontally the root of the neck on the outer face of 
the scaleni muscles above the subclavian artery. It gets under the 
anterior margin of the trapezius, and is there divided into two prin- 
cipal branches; the ascending one is spent upon the trapezius and 
the levator scapulae; the other descends along the base of the 
scapula, and is spent in ramifications upon the rhomboidei and the 
serratus major muscle. Several branches of minor size and import- 
ance are sent off" from the posterior cervical artery to the muscles 
on the back of the neck and thorax. 

The Subclavian Artery having sent off the preceding branches, 
then escapes from the thorax between the scaleni muscles, and gets 
to the arm-pit between the first rib and the subclavius muscle. The 
trunk of it is then continued downwards through the axilla, and at 
the inner side of the arm to the elbow joint. 

From the scaleni muscles to the elbow its relative position is as 
follows: When it first appears between the scaleni, it is bounded 
above and behind by the collected fasciculi of the axillary plexus 
of nerves. In front it is separated from the subclavian vein by the 

Vol. II.— 22 



246 CIRCULATORY SYSTEM. 

insertion of the scalenus anticus. It is placed at the bottom of the 
depression between the sterno-raastoideus and the trapezius, being 
covered by the skin, the platysma rayodes, and some loose cellular 
substance below the latter. It then descends between the first rib 
and the subclavius muscle; escaping from below the latter, it is 
covered in front by the outer margin of the pectoralis major until it 
reaches the lower part of the axilla; and in this course it has the 
following relation to other parts: it passes first under the insertion 
of the pectoralis minor, then under the shoulder joint, then along 
the internal face of the coraco-brachialis muscle; it has the axillary 
vein in front of it, and the axillary nerves plaited around it as far 
down as the coracoid process, when they begin to disperse. This 
artery in emerging from the axilla is placed upon the anterior face 
of the insertion of the latissiraus dorsi: it then runs out the length 
of the coraco-brachialis, and is afterwards conducted along the inner 
margin of the biceps flexor cubiti and of its tendinous termination ; 
it lies upon the anterior face of the brachialis internus; and goes 
beneath the aponeurosis coming from the tendon of the biceps at 
the bend of the arm. In the arm it is concealed only by the integu- 
ments and fascia, and is bordered internally by the brachial vein 
and the median nerve. 

This great trunk of the upper extremity loses the name of sub- 
clavian, to be called Axillary Artery, [Art. Axillaris,) from the sub- 
clavian muscle to the lower margin of the arm-pit : and from the 
latter place to the elbow-joint, it is named Brachial Artery, {Art. 
Brachialis.) It sends off many interesting branches to the thorax, 
to the shoulder, and to the arm ; and, finally, terminates a little be- 
low or at the elbow joint by bifurcating. 



Of the Branches of the Axillary Artery. 

1. The Superior Scapular Artery (Art. Borsalis Superior Scapula) 
varies considerably in its origin. Sometimes it is a branch of the 
subclavian, sometimes of the inferior thyroid, and it frequently 
comes from the upper part of the axillary ; so that it cannot be re- 
ferred, with strict propriety, to any determined origin. When it 
comes from the axillary, it is very tortuous, and has to ascend to its 
destination, which removes it entirely from any interference with the 
course of the subclavian over the first rib, and over the upper head 



AXILLARY, AND ITS BRANCHES. 247 

of the serratus major muscle. But in the other cases, it goes trans- 
versely backwards and outwards, somewhat below the posterior cer- 
vical, and along the posterior inferior margin of the clavicle, being 
covered by the sterno-mastoideus, the platysma myodes, and the 
trapezius ; consequently, it is just in the way of the incisions which 
are made for reaching the subclavian artery, from above the clavicle. 
It reaches the superior costa of the scapula near the root of the 
coracoid process, and passing through the notch there, is distributed, 
by one large branch, upon the supra spinatus muscle ; and by another, 
which goes across the anterior margin of the spine of the scapula, to 
the infra-spinatus muscle. In its course, it sends off several small 
ramifications to contiguous parts. 

2. The External Mammary Arteries (Art. Mammarice seu Tho- 
racica Externa) arise from the axillary, between the subclavius and 
the pectoralis minor muscle. There are four principal trunks, which 
go uniformly to certain parts, but vary considerably in their origin ; 
for sometimes the latter is distinct in the case of each artery, but 
frequently otherwise. Their distribution is as follows: 

a. The Thoracica Superior is distributed to the upper part of the 
pectoralis major muscle, and to the pectoralis minor. Some of its 
branches reach the mamma in the female, and anastomose with the 
internal mammary and with the intercostals. 

b. The Thoracica Longa descends along the posterior face of the 
pectoralis major, between it and the serratus magnus. It gives many 
branches to the lower part of the pectoralis major, to the integuments j 
and, in the female, to the mamma ; anastomosing likewise with the 
internal mammary and with the intercostals. 

c. The Thoracica Acromialis, immediately after its origin, makes 
for the fissure betw r een the deltoid and the great pectoral muscle, 
and divides there into an ascending and a descending branch. The 
former reaches the clavicle, and is partly distributed superficially 
along it, partly to the contiguous muscles, and to the shoulder arti- 
culation. The other branch follows the cephalic vein along the in- 
terstice between the deltoides and pectoralis major, and is, finally, 
distributed to these muscles and to the integuments. 

d. The Thoracica Axillaris is irregular, both in regard to the 
number of its branches and to their origin. Instead of a distinct 
origin by one or more trunks from the axillary artery, the branches 
belonging to the name of thoracica axillaris, are sometimes derived 



248 CIRCULATORY SYSTEM. 

from the other thoracic arteries. They are generally distributed only 
to the fat and the lymphatic glands in the axilla. They occasionally 
exist primitively as a large trunk, which runs on the scapular face of 
the serratus major the whole length of the scapula, and is distributed 
to the adjacent muscles, and to the fat and glands of the axilla. 

3. The Scapular Artery [Arteria Scapularis communis, Subscapu- 
laris) arises from the axillary below the shoulder joint, at or near the 
anterior margin of the subscapularis muscle. Giving off some in- 
considerable branches to the lymphatic glands of the arm-pit, it 
descends along the anterior margin of the subscapularis, and is dis- 
tributed to it, to the latissimus dorsi, and to the teres major and 
minor muscles. 

A little below the neck of the scapula, it detaches a large trunk, 
the Dorsalis Inferior Scapula?, which winding around the inferior 
costa of the bone over the anterior margin of the subscapularis and 
the teres minor, reaches the fossa infra-spinata. This trunk then 
divides into two branches : one of which is distributed superficially 
between the scapular aponeurosis and the infra-spinatus, and the 
other more deeply near the dorsum of the bone : one of the ramus- 
cles of the latter ascends beneath the neck of the acromion to anas- 
tomose with the Dorsalis Superior Scapulas. 

4. The Anterior Circumflex Artery {Art. Circumflexa Anterior, 
Articularis Anterior) is about the size of a crow quill, and arises 
from the axillary just above the tendon of the teres major and of the 
latissimus dorsi. It adheres closely to, and surrounds the front of 
the neck of the os humeri, passing between it, the coraco-brachialis, 
and the short head of the biceps. It then divides into several 
branches, some of which go to the deltoides, and anastomose there 
with the posterior circumflex ; others go immediately to the articula- 
tion, and either terminate on it or ascend to the muscles on the 
dorsum of the scapula, where they anastomose with the scapular 
arteries. 

5. The Posterior Circumflex Artery [Art. Circumflexa Posterior) 
is much larger than the last, and arises from the axillary somewhat 
below it. It surrounds the posterior face of the neck of the os 
humeri, passing between it and the long head of the triceps muscle, 
below the insertion of the teres minor. Many of its ramifications 
go to the capsular ligament of the articulation and to the muscles 



BRACHIAL, AND ITS BRANCHES. 249 

adhering to it. But this artery is principally intended for the deltoid 
muscle, to the internal face of which the most of its branches go. 
It anastomoses with the anterior circumflex, and with the scapular 
arteries. 

In some cases, the posterior circumflex arises from the axillary, 
below instead of above, the tendinous insertion of the latissimus 
dorsi : when this happens, it commonly gives off the arteria profunda 
major of the arm, and afterwards ascends on the posterior face of the 
tendon to its appropriate destination. 



Of t/te Branches of tlie Brachial Artery.. 

1. The Profound Artery (Arteria Profunda Major Humeri, Spi- 
ralis,) arises from the brachial, a little below the tendinous insertion 
of the latissimus dorsi, and having passed downwards, for a short 
distance, it enters the interstice between the first and the third head 
of the triceps muscle, and winds spirally downwards around the os 
humeri in company with the radial nerve. On the outer side of the 
arm, it becomes superficial between the margins of the triceps and 
of the brachialis internus, and then directs its course between the 
latter and the supinator longus to the external condyle. 

In this course, the artery sends several branches to the triceps 
muscle, to which, indeed, it is principally destined. Near the ex- 
ternal condyle, it supplies the brachialis internus and the heads of 
the extensor muscles of the fore-arm, and anastomoses with the 
recurrent branch of the radial artery. 

2. The Small Profound Artery (Art. Profunda Minor) comes 
from the brachial, two or three inches below the profunda major, 
but frequently it is only a branch of the latter, and is generally much 
smaller. It is distributed superficially on the internal face of the 
triceps at its lower part, and has its terminating branches reaching 
as far as the internal condyle. 

3. The Nutritious Artery (Art. JYutritia) is the next in order 
from the brachial, and arises from it near the medullary foramen of 
the os humeri, through which it penetrates, and is distributed to 
the lining membrane of the bone. It is not larger than a knitting 
needle. 

22* 



250 CIRCULATORY SYSTEM. 

4. The Anastomotic Artery [Arteria Anastomotica) arises from 
the brachial below the last, and is larger than it. It lies upon the 
lower internal part of the brachialis internus muscle, and crosses the 
ridge leading to the internal condyle in order to reach the depression 
between the latter and the olecranon, where it anastomoses with the 
ulnar recurrent artery. 

The preceding is a common arrangement of the branches pro- 
ceeding from the brachial artery, yet deviations from it are continu- 
ally met with, in a deficiency or in a redundancy of these collateral 
trunks, and in their mode of origin. An account of all the varieties 
which are observed here would be almost endless, as every subject 
has some peculiarity. Several small arteries are also sent from the 
brachial to the coraoo-brachialis, the biceps, the brachialis internus, 
and to the triceps muscle. They, for the most part, are, simply, 
muscular branches, which are too small and irregular to deserve spe- 
cifying. 

A division of the brachial artery into two trunks, the Radial and 
the Ulnar, will be found in a majority of subjects in front of the 
brachialis internus muscle on a line with the elbow joint: sometimes 
it occurs nearer the root of the coronoid, process. It is, however, 
by no means rare to see this bifurcation much above the elbow. 
Examples of it have been witnessed at every point between the latter 
and the arm-pit ; in such cases, the course of the radial artery down 
the fore-arm is generally much more superficial than usual, as it is 
placed immediately below the skin. 



Of the Radial Artery. 

The Radial Artery {Arteria Radialis) is smaller than the ulnar, 
and extends from the elbow to the hand. In the upper half of the 
fore-arm it is placed at the bottom of the fissure between the supi- 
nator radii longus and the pronator teres muscle. Having crossed 
the insertion of the latter, it runs in front of the radius between the 
tendon of the supinator and of the flexor carpi radialis. Below 
the styloid process of the radius it runs between the outer end of 
the carpus and the extensor muscles of the thumb ; it then pene- 
trates to the palm of the hand between the root of the metacarpal 



RADIAL ARTERY. 251 

bone of the thumb and of the fore-finger above the abductor indicis 
muscle. 

The following branches are sent from the Radial Artery. 

1. The Recurrens Radialis arises at the neck of the radius. It 
winds, externally around the joint between the external condyle 
and the muscles coming from it, and anastomoses with the spiralis 
of the humeral artery, being distributed in many collateral branches, 
to the joint and to the contiguous muscles. 

2. Several small and irregular muscular branches arise from the 
radial artery, in its progress to the wrist : they have no appropriate 
names. 

3. The Superficialis Volee arises from the radial about the infe- 
rior margin of the pronator quadratus muscle. It passes superfi- 
cially over the process of the trapezium to the muscles of the ball 
of the thumb, and one of its terminating branches joins the arcus 
sublimis. Sometimes the superficialis volse is the principal branch 
of the radial. 

4. The Dorsalis Carpi arises from the radial at the carpus, runs 
across the back of the latter below the extensor tendons, and de- 
taches the posterior interosseous arteries of the back of the hand. 
They anastomose w T ith branches from the ulnar and interosseous arte- 
ries of the fore-arm. 

5. The Magna Pollicis, a terminating branch of the radial, comes 
from it in the palm of the hand just at the root of the metacarpal 
bone of the thumb. It runs beneath the abductor indicis, and at 
the head of the metacarpal bone divides into two branches which 
go respectively along the sides of the thumb to its extremity, where 
they anastomose and terminate. 

6. The Radialis Indicis, arising at the same place with the latter, 
runs along the metacarpal bone of the fore finger, and along the 
radial side of the same finger to its extremity. 

7. The Palmaris Profunda is the third terminating branch of the 
radial artery. It arises near the same place with the last two, crosses 



252 CIRCULATORY SYSTEM. 

the hand between the metacarpal bones and the flexor tendons ; thus 
forming the Arcus Profundus, from which branches proceed to the 
interossei muscles ; and which ends on the ulnar side of the palm of 
the hand by a connexion with the Arcus Superficialis. 



Of the Ulnar Jfaiery. 

The Ulnar Artery, {Arteria Ulnaris,) one of the forks of the 
brachial at the elbow, passes more in a line with it than the radial 
artery does. It goes, immediately after its origin, under several 
of the muscles of the internal condyle, to wit : the pronator teres, 
flexor radialis, flexor sublimis, and palmaris longus, and between 
the flexor sublimis, and profundus digitorum, being deeply seated; 
getting from beneath the flexor sublimis, it afterwards runs parallel 
with the ulna, or nearly so, lying on the flexor profundus between 
the flexor ulnaris and the ulnar margin of the flexor sublimis, and 
concealed two-thirds of the way down the fore arm by the over- 
lapping of these muscles. At the thin part of the fore arm, com- 
monly called the wrist, it is superficial, and may be felt pulsating 
in the living body at the radial margin of the tendon of the flexor 
ulnaris. 

The ulnar artery, at the carpus, takes a very different course from 
the radial ; for it passes over the anterior annular ligament of the 
carpus just at the radial side of the os pisiforme, to which it is held 
by a small ligamentous noose ; it then proceeds to the palm of the 
hand. Between the aponeurosis palmaris and the flexor tendons it 
forms that curve from the ulnar to the radial side of the hand called 
the Arcus Sublimis. This curve commonly begins a little beyond 
the anterior margin of the annular ligament, and presenting its con- 
vexity forwards, terminates about the middle of the ball of the thumb 
at its inner margin. 

The branches sent from the ulnar artery are as follow : 

1. The Recurrens Ulnaris arises from the ulnar about the lower 
part of the tubercle of the radius, and, winding upwards, is distri- 
buted in small branches to the muscles of the internal condyle. One 
of its ramuscules goes between the internal condyle and the olecranon 
process to anastomose with the arteria anastomotica of the humeral. 



ULNAR ARTERY. 253 

2. The Interossea arises from the ulnar, just below the other. It 
is a large trunk, and proceeds but a little distance when it divides 
into two principal branches, called anterior and posterior interosseal 
arteries. . 

a. The Interossea Anterior is much the larger ; it runs in contact 
with the interosseous ligament to the upper margin of the pronator 
quadratus, giving off branches to the deep-seated muscles of the fore 
arm in its course. Under the pronator it perforates the interosseous 
ligament, and distributes branches to the back of the carpus and of 
the hand, which anastomose with branches of the radial and posterior 
interosseal. 

b. The Interossea Posterior is sometimes a separate trunk, arising 
from the ulnar just above the former. In either case it soon per- 
forates the interosseous ligament to get to the back of the fore arm. 
Here it sends backwards a Recurrent Branch [Recurrens Interossea) 
to the back of the elbow, which anastomoses with the recurrens 
ulnaris and radialis. It then proceeds downwards, being deeply 
seated and distributed to the different muscles on the back of the 
fore arm. Some of its branches reach the wrist, and anastomose 
with the carpal arteries. 

3. The ulnar artery, in its descent on the fore arm, sends off many 
small and irregular muscular branches, called by Professor Chaussier, 
Cubito-muscular : they do not require description. 

4. The Dorsalis Manus leaves the ulnar at the lower end of the 
fore arm, and passes under the tendon of the flexor ulnaris to the 
back of the hand. It there meets ramuscules of the radial and inter- 
osseous, and conjointly they supply with very small branches the 
back of the wrist, of the metacarpus, and of the fingers. 

5. As the Arcus Sublimis is about beginning, the ulnar artery 
sends superficial but small branches to the integuments of the palm; 
and a little farther on, a considerable branch, which dives into the 
bottom of the palm, through the muscles of the little finger, and joins 
the ulnar extremity of the arcus profundus : this is the Cubitalis 
Manus Profunda of Haller. 

C. The Arcus Sublimis then sends a branch to the ulnar side of 



254 CIRCULATORY SYSTEM. 

the little finger. Afterwards in succession three digital branches are 
sent off, which, arriving at the interstices between the heads of the 
several metacarpal bones, each divides into two branches to supply 
the sides of the fingers which are opposite to each^other ; one branch 
is called Digito-radial, the other Digito-ulnar, according to the side 
of the finger on which the artery may be placed. In this way the 
radial side of the little finger, both sides of the ring finger, both sides 
of the middle finger, and the ulnar side of the fore finger are sup- 
plied. 

The digital arteries, before they divide, receive each a small 
branch from the arcus profundus. The digito-radial, and the digito- 
ulnar arteries, pass along the sides of the fingers in front to their ex- 
tremities; at the joints and extremities, many anastomoses between 
the arteries of the two sides of the same finger occur. 

The arcus sublimis terminates on the radial side of the palm by 
a branch which joins the inner branch of the Arteria Magna Pollicis 
of the Radial. 

The most frequent distribution of the arteries of the hand is what 
has just been described : anatomists are, however, not all agreed on 
this point. It would probably be more just to say, that this occurs 
more frequently than any other single arrangement. The varieties, 
in fact, are so great, that before a hand is opened, it is not possible 
to know in what manner its arteries will be distributed. Sometimes 
the Radial Artery furnishes one half of the arcus sublimis, and the 
Ulnar the other half. On other occasions, the interosseous artery, 
or the superficialis volse, is continued as a large trunk over the liga- 
ment of the wrist, to join the arcus sublimis, and to complete the 
digital arteries. 

SECT. IV. — BRANCHES OF THE DESCENDING THORACIC 
AORTA.* 

The Aorta, in its course from the lower part of its curvature to 
the crura of the Diaphragm, gives off several branches to the viscera 
and to the parietes of the thorax. 

The Bronchial Arteries {Arteries Bronchioles) are the nutritious 
vessels of the lungs. There is commonly one for each lung, but 

*Anat. Atlas, Fig. 461. 



DESCENDING AORTA. 255 

sometimes two or more. The right arises frequently from the supe- 
rior aortic intercostal artery, instead of from the aorta, while the left 
comes from the latter : occasionally they have a common root. 

On either side they follow the course of the bronchus into the 
substance of the lung ; and are distributed along with it, by ramifi- 
cations which become successively finer and finer, and anastomose 
with the pulmonary artery; after the manner mentioned in the de- 
scription of the lungs. Before they enter the latter, they send some 
small ramifications to the posterior mediastinum, to the pericardium, 
and to the black bronchial glands. 

The (Esophageal Arteries (Arterice (Esophagece) are generally five 
or six small twigs which come successively from the descending 
thoracic aorta. They ramify minutely in the substance of the oeso- 
phagus, communicating freely with each other: the lowest of them 
also anastomose around the cardia with the superior artery of the 
stomach. 

The Posterior Arteries of the Mediastinum, (Arterice Mediasti- 
nales Posteriores,) are numerous and small ; they come from the 
anterior face of the aorta, as well as from the branches last men- 
tioned; and are spent upon the posterior mediastinum, and upon 
its contents. 

The Intercostal Arteries (Arterice Intercostales Inferiores, Aorticce) 
of the aorta supply the ten lower intercostal spaces on each side, as 
the two upper ones are supplied by the subclavian artery. There is 
commonly an intercostal artery arising distinctly from the aorta for 
e^eh space, but sometimes two of them arise from a common trunk. 
Those for the right side having to cross the spine behind the oeso- 
phagus and the vena azygos, are, of course, longer than such as be- 
long to the left. The upper ones on either side have to ascend, in 
order to reach their destination. 

Each artery joins the rib near its tubercle, and goes along the 
groove in its lower margin, between the external and the internal 
intercostal muscle, for two-thirds of the length of the rib. It then 
abandons the groove, and divides into several branches, which go 
to the intercostal muscles and contiguous parts, and anastomose in 
front with the internal mammary artery. 

As each intercostal artery passes the head of the rib, it sends a 



256 CIRCULATORY SYSTEM. 

branch backwards; (ramus dorsalis,) between the transverse pro- 
cesses of the adjoining vertebrae, which penetrates to the posterior 
face of the trunk, and is distributed to the muscles and skin on the 
side of the spine. A ramification from this branch enters the inter- 
vertebral foramen, and is spent upon the medulla spinalis and its 
membranes. 

Each intercostal artery also gives off, about the middle of the rib, 
a branch, (ramus costalis inferior,) much smaller than the trunk. 
This branch advances along the upper margin of the rib below, and 
gives ramifications to its periosteum and to the adjacent intercostal 
muscles. 

The last intercostal artery is remarkable for its size. Its origin is 
concealed by the small muscle of the diaphragm, to which it gives 
some ramifications : it then passes, at the under margin of the last 
rib, behind the upper end of the quadratus lumborum muscle, where 
it divides into three branches ; one of which goes transversely to the 
broad muscles of the abdomen ; while the other two descend be- 
tween the oblique and transverse muscles towards the crest of the 
ilium, where they anastomose with the lumbar arteries, and with the 
circumflexa ilii. 



SECT. V. — OF THE BRANCHES OF THE ABDOMINAL AORTA.* 

The Phrenic Arteries (Arterice Phrenicce) are two in number, one 
for the right and the other for the left side of the diaphragm. They 
arise singly, but sometimes by a common trunk, from the front of 
the aorta, immediately on the latter showing itself in the abdomen, 
between the crura of the diaphragm ; consequently, just below the 
crossing of the muscular fibres, which takes place between the 
foramen for the aorta and that for the oesophagus. 

The phrenic arteries ascend along the lesser muscle of the dia- 
phragm, and give some ramifications to it and to the capsular re- 
nales. They then divide each into two leading trunks, which are 
distributed over the diaphragm, principally on its concave surface. 
Some small ramifications from them go to the liver and to the lower 
part of the oesophagus. 

The two phrenic arteries anastomose with each other : also, with 

* Anat. Atlas, Figs. 462 to 465, inclusive. 



BRANCHES OF THE ABDOMINAL AORTA. 257 

the superior phrenics, coming from the internal mammary ; and with 
the intercostals. Sometimes one or both of them come from the 
cceliac artery, or its branches. 

The Ccfiliac Artery {Arteria Cceliaca) is the next branch of the 
abdominal aorta, and arises immediately below the phrenics, between 
the crura of the diaphragm, opposite the junction of the last dorsal 
with the first lumbar vertebra. It is a very large trunk, and goes 
off at right angles, being placed between the left lobe of the liver and 
the superior margin of the pancreas. When it is only half an inch 
long, it is split into three trunks, the Gastric, the Hepatic, and the 
Splenic ; this division is the Tripus Halleri. 

The Gastric Artery [Arteria Gastrica, Coronaria Ventriculi) is 
the smallest of the three trunks, and frequently arises from one of 
the others. It advances forwards and towards the cardiac orifice in 
order to reach the small curvature of the stomach, the course of 
which it pursues to the pylorus, between the two laminae of the 
smaller omentum. It gives off the following branches : — 

a. Ramifications to the oesophagus, some of which ascend along 
it into the posterior mediastinum, and anastomose there with the 
similar branches coming from the aorta ; others go transversely, so 
as to surround the cardia, reach the greater end of the stomach, and 
anastomose with the vasa brevia. 

b. The ramifications to the stomach are abundant, but of an in- 
determinate number, and arising along its lesser curvature, are dis- 
tributed in winding branches to the anterior and the posterior sur- 
faces of this viscus, between its membranes. 

c. Not unfrequently the artery which supplies the left lobe of the 
liver is a branch from the gastric, in which case the latter is much 
larger than usual. 

2. The Hepatic Artery (Arteria Hepatica) is generally consider- 
ably larger than the gastric, and inclines towards the right side, in 
order to reach the liver, which it does through the capsule of Glisson. 
It sends off the following branches: — 

a. The Right Gastric or Gastro-Epiploic Artery (Arteria Gas- 
trica Dextra) comes from it near the pylorus, and descending be- 
tween the duodenum and pancreas, reaches the greater curvature 
of the stomach, to the right half of which, and to the correspond- 

Vol. II.— 23 



258 CIRCULATORY SYSTEM. 

ing part of the great omentum, it is distributed. In the early part 
of its course, the right gastric detaches some small ramifications to 
the pylorus (arterice pyloricce ;) also, to the duodenum and to the 
pancreas (art. pancreatico-duodenales.) The latter communicate, by 
very free anastomoses, with the superior mesenteric artery. 

After having sent off' this branch, the hepatic artery advances to 
the transverse fissure of the liver, in front of and to the left of the 
vena portarum. It then divides into a right and a left branch. 
The former sends off* a ramification to the gall-bladder, (Art. Cys- 
tica,) which first reaches its neck, and is distributed, by many arte- 
rioles, upon the parietes of this reservoir ; the right branch then 
penetrates deeply into the transverse fissure, and is distributed by 
many ramifications, throughout the right lobe of the liver. The left 
branch of the hepatic artery is distributed, in the same manner, 
throughout the left lobe of the liver. 

3. The Splenic Artery (Arteria Splenica) is larger in the adult 
than either of the other two branches of the cceliac, and goes to the 
spleen along the superior margin"of the pancreas, performing, in this 
course, several considerable flexuosities. It gives off the following 
branches : — 

a. The Pancreatic Arteries, (Art. Pancreatic^ Medice et Sinistra) 
come successively from its inferior margin, as it goes along the pan- 
creas. Their number and size are variable, but commonly they are 
not bigger than a knitting needle ; they penetrate perpendicularly 
into the pancreas, and then subdivide minutely in furnishing its 
structure. 

b. The Left Gastric Artery (Art. Gastrica Sinistra, Gastro-epi- 
ploica Sinistra) comes from the left extremity of the splenic, and is 
about the same size with the right gastric artery, but sometimes 
larger. It attaches itself to the left extremity of the stomach, and 
goes along the left half of its greater curvature, terminating by an 
anastomosis with the right gastric artery. In this course, it detaches 
ramifications to the front and to the back of the stomach, and to the 
omentum majus. 

c. The Short Vessels ( Vasa Brevia, Art. Gastrica Breves) come 
from the splenic, immediately before it enters the Spleen, and after 
it has subdivided for that purpose. They are five or six in number, 
and are distributed upon the greater extremity of the stomach, be- 
tween the cardia and the left gastric artery. The anastomoses 



BRANCHES OF THE ABDOMINAL AORTA. 259 

between the several arteries of the stomach are so free, that a fine 
injection pushed into one, readily finds its way into all the others. 

The splenic artery, when it gets to the left end of the pancreas, is 
divided into a cluster of branches, and in that condition enters the 
fissure of the spleen, throughout the interior of which it is divided 
into innumerable ramifications. 

The Superior Mesenteric Artery (Arteria Mesenterica Superior) 
arises from the aorta, while the latter is still engaged, between the 
crura of the diaphragm. It is about the same size as the cceliac, and 
comes off half an inch below it. It is distributed to all the small 
intestines and to the right side of the large one after the following 
manner : it first passes behind the pancreas, and then in front of the 
duodenum, to reach the root of the mesentery, between the two la- 
minae of which it divides and subdivides into several series of arches, 
one after another : they become successively smaller and more nu- 
merous till they reach the margin of the intestine, where they cease 
by sending a great many small parallel branches. 

The trunk of the superior mesenteric artery, in descending be- 
tween the lamina of the mesentery, describes a considerable curva- 
ture, the convexity of which is to the left side and downwards, while 
its concavity is in a contrary direction. It is from the convexity of 
this trunk, that from fifteen to twenty large branches are sent off suc- 
cessively to form the roots of the first row of arterial arches. These 
branches are shorter, and generally somewhat smaller, the lower 
down they arise , and their origins very closely succeed each other. 
Upon the first row of arches or anastomoses is formed a second more 
numerous and small, and upon the second row is formed a third still 
more numerous and small, from which proceed the intestinal branches. 

Besides the preceding branches, the superior mesenteric artery 
sends off the following: 

Near its root several small ramifications arise, which go to the 
duodenum and to the pancreas, and anastomose there with the other 
arteries supplying the same organs. 

From about the middle of the concavity of the superior mesen- 
teric artery, arise the three Colic arteries called Ileo-colica, Colica 
Dextra, and Colica Media : the first supplies a cluster of branches 
to the lower part of the ileum and to the head of the colon, anasto- 
mosing on the left with the last of the small intestinal arteries and 
on the right with the colica dextra: the Colica Dextra is smaller 



260 CIRCULATORY SYSTEM. 

than either of the other two branches, and going between the laminse 
of the mesocolon, supplies the ascending portion of the colon by 
dividing into two principal branches, one of which anastomoses 
with the ileo-colic artery, and the other with the colica media : the 
Colica Media, situated between the laminae of the transverse meso- 
colon, and arising higher up than the colica dextra, advances for- 
wards and divides into two principal trunks ; one of which supplies 
that part of the colon in the right hypochondriac region, and the 
other the remainder of its transverse portion, forming an anasto- 
mosis with the colica superior of the inferior mesenteric artery. 
The arteries which supply the colon differ from those supplying the 
small intestines, in forming but one row of arches ; which, in fact, 
are produced by the anastomoses spoken of, and have, therefore, ex- 
tremely large meshes. From the convexity of these arches, many 
parallel branches run out to supply the colon, and are very minutely 
distributed to it. 

The Capsular Arteries, the Emulgents, and the Spermatics, arise 
from the aorta, between the superior and the inferior mesenteric. 
But they will be described after the inferior mesenteric, so as to 
keep together the account of the arteries of the intestines. 

The Inferior Mesenteric Artery, {Art. Mesenterica Inferior) gene- 
rally arises about one inch above the division of the aorta into the 
two primitive iliacs, and is much smaller than the superior Mesen- 
teric. It inclines downwards to the left side, and gets between the 
laminas of the mesocolon ; it then divides into three branches, called 
the Left Colic Arteries, from their distribution to the left side of the 
colon. From their relative situation to each other, they are distin- 
guished into the Superior, the Middle, and the Inferior ; sometimes, 
however, there are but two of these trunks. 

The Superior Colic (Art. Colica Sinistra Superior) goes horizon- 
tally towards the colon in the left lumbar region ; having got near 
the intestine it divides into two branches, one of which ascends to 
the transverse colon to form the anastomosis with the Colica Media 
of the upper mesenteric, while the other descends to unite with the 
colica media sinistra. The Middle Colic Artery (Art. Colica Sin- 
istra Media) is sometimes a branch of the superior, and is occasion- 
ally wanting; it goes towards the upper part of the sigmoid flexure 



BRANCHES OF THE ABDOMINAL AORTA. 261 

of the colon, and then bifurcates: one branch ascends to form by 
anastomosis an arch with the superior colic, while the other branch 
descends to join the lower colic artery. The Inferior Colic Artery 
{Art. Colica Sinistra Inferior) goes towards the middle of the sigmoid 
flexure of the colon, and there, like the preceding, divides into two 
branches ; one anastomoses with the artery above, while the other 
joins with the arteries which go to the rectum from the inferior 
mesenteric. 

The Superior Hemorrhoidal Artery (Art. Hatmorrhoidea Superior^ 
Interna,) is the lowest and the last branch of the inferior mesenteric. 
It descends between the laminae of the mesore.ctum, and is resolved 
into two symmetrical trunks, which radiate by dividing and sub- 
dividing on the side of the rectum, and are dispersed in very fine 
and numerous branches throughout its substance. It anastomoses 
with the middle and the inferior hemorrhoidal arteries, also with 
the lateral sacral. 

The Capsular Arteries (Art. Capsulares) arise frequently from the 
aorta just below the superior mesenteric ; but quite as often, if not 
more so, from the emulgents. They are not larger than a crow's 
quill, and vary from one to three on either side; generally however 
not exceeding one: and when they do, they are proportionablv 
small. Passing horizontally outwards, they divide into several 
small ramifications, which terminate in the capsulse renales. Some 
of their branches go to the lesser muscle of the diaphragm. 

The Emulgent Arteries (Art. Emulgentes, Renales,) are two in 
number, one for each kidney, but sometimes more. They are large 
but short; arise from the side of the aorta immediately below the 
superior mesenteric, and pass outwardly in a horizontal direction. 
The right one is longer than the left, somewhat lower down, and 
passes behind the ascending cava. They are both, in their course, 
from the aorta to the kidney, covered in front by the emulgent vein, 
and have to pass through a mass of adipose matter. 

The emulgent sends oil" some fine ramifications to the adipose 
matter, which surrounds it, and before it reaches the fissure of the 
kidney divides into three or four branches, preparatory to its intro-* 
duction into this gland, upon the structure of which it is ultimately 
distributed by very fine branches. 

23* 



262 CIRCULATORY SYSTEM. 

The Spermatic Arteries {Arteries, Spermatica, Seminales,) arise 
from the aorta somewhat below the emulgents, but in some cases 
from the latter themselves. They are two in number, one on each 
side, and are about the size of a crow quill in the male subject, but 
smaller in the female. One comes off" generally higher up than the 
other; they then descend on the sides of the Yertebral column before 
the psoae muscles, and cross in front of the ureters, being in all this 
course behind the peritoneum. They are tortuous, and shortly after 
their origin begin to adhere to the spermatic veins, which adhesion 
is continued to the testicle. 

The branches that the spermatic artery sends off in the abdomen 
are inconsiderable, consisting in very fine twigs to the adjacent 
adipose matter, to the lymphatic glands, to the ureter, and to the 
peritoneum. In the male subject it passes with the vas deferens, 
through the abdominal canal, and reaching the testicle divides into 
branches which supply the body of this gland and the epididymis. 
In descending from the external ring to the testis, some small rami- 
fications, to the adjacent parts, leave it. In the female, the sper- 
matic artery does not leave the cavity of the abdomen, but, de- 
scending into the pelvis, gets between the laminae of the broad 
ligament to the ovarium, and is spent principally upon the latter. 
Some of its branches go to the Fallopian Tube, to the Round Liga- 
ment of the uterus, and to the sides of the latter, where they anas- 
tomose with the uterine arteries.* 

The Lumbar Arteries (Arterice Lumbares) are commonly five in 
number on either side, but seldom less than three, and in their course 
outwards, correspond with the intercostal arteries. They are much 
larger than the latter. They arise in pairs from the posterior external 
lace of the aorta, at a point corresponding with the middle of the 
bodies of the four upper lumbar vertebrae, and pass outwards be- 
tween the fasciculi of the psoas magnus muscle, to which, to the 
quadratus lumborum, and the bodies of the vertebrae, they distribute 
several branches. Sometimes each pair arises by a common trunk 
from the posterior face of the aorta. As the latter terminates at the 
fourth lumbar vertebra, the fifth lumbar artery is a branch from the 
fourth in most instances. 

* The spermatic artery is spindle-shaped, the smallest end being the origin; 
this favours the flow of blood in it, which would otherwise suffer from so much 
friction. 



BRANCHES OF THE ABDOMINAL AORTA. 263 

At the base of the transverse process each artery divides into two 
branches, a posterior or dorsal one, and an anterior or lumbar. 
The dorsal branch, which is smaller than the other, detaches a ra- 
mification through the intervertebral foramen to the lower part of the 
medulla spinalis and to the Cauda equina: it then gets to the back, 
where it is spent upon the muscles near the spine. The anterior 
lumbar branch advances between the broad muscles of the abdomen 
to which it is distributed ; and runs forwards far enough to anasto- 
mose with the epigastric artery. 

The first lumbar artery is the smaller, and sometimes comes from 
the last intercostal : it goes a little below the inferior margin of the 
last rib, and then descends almost vertically between the peritoneum 
and the transversalis abdominis muscle. The lower lumbar arteries 
anastomose with the circumflexa ilii, and with the superficial branches 
of the gluteal. 

The Middle Sacral Artery (Arteria Sacra Media) is generally not 
so large as a lumbar ; it arises from the centre of the bifurcation of 
the aorta into the two primitive iliacs, or else a line or two above it, 
behind. It descends, in front of the middle line of the fifth lumbar 
vertebra and of the sacrum, to the coccyx adhering to the surface of 
these bones, and performing some flexuosities. 

It sometimes happens that the last pair of lumbar arteries comes 
from it, or at least one, according to Meckel, more commonly the 
left: in which case the sacral is of unusual size. The sacral after- 
wards sends off, to the right and left, a pair of branches for each 
pair of sacral foramina. They run across the sacrum, send branches 
to it, anastomose with the lateral sacral arteries, and then penetrate 
to the cauda equina. The middle sacral artery is lost at the inferior 
end of the coccyx, in the fat and cellular tissue of the part. 



SECT. VI. — OF THE PRIMITIVE ILIAC ARTERIES, AND THEIR 
BRANCHES. * 

The Primitive Iliac Arteries, [Art. IHacce Primitive communes,) 
one on each side, are, as mentioned, the terminating trunks of the 
abdominal aorta. They extend from the lower part of the fourth 

* Anat. Atlas, Fig. 465. 



264 CIRCULATORY SYSTEM. 

lumbar vertebra to the sacro-iliac junction, or near it, where they 
divide into two trunks, the Internal and the External Iliac. This 
division however not unfrequently occurs at the inferior lateral edge 
of the fifth, lumbar vertebra, near the base of the sacrum. 

The primitive iliac is bounded on the outer side by the psoas 
magnus muscle, and behind by the primitive iliac vein ; it is crossed 
at its lower part by the ureter. No branches deserving of especial 
notice are sent from it before it bifurcates ; such as exist are very 
small, and go simply to the parts immediately contiguous. The 
right artery crosses in front of the root of the left iliac vein. 



SECT. VII. — OF THE INTERNAL ILIAC, OR THE HYPOGASTRIC 

ARTERY.* 

The Internal Iliac Artery (Art. Iliaca Interna, Hypogastrica) 
descends from its origin near the front upper part of the sacro-iliac 
junction, to the lower part of the same articulation. In this descent, 
it is bounded behind by the sacral plexus of nerves, and gives off 
several arterial trunks ; but the manner by which the last is accom- 
plished is much varied in different subjects. For the most part, it 
is an inch or more long before any important branches leave it ; it 
is then frequently divided into two principal trunks, an anterior and 
a posterior, from which proceed the several branches that supply 
the internal and the external parts of the pelvis. The rule of ori- 
gin of the secondary trunks from these two principal ones, even 
when the latter exist, is not fixed ; for sometimes they arise from 
one, sometimes from the other, and then 'again from the trunk of 
the hypogastric itself. 

The Ilio-Lumbar Artery (Art. Ilio Lumbaris) is commonly the 
first branch of the hypogastric, or of its posterior trunk. It ascends 
outwards and backwards behind the psoas magnus muscle, and 
there divides into two branches, a superior and an inferior. The 
former continues to ascend between the psoas magnus and the iliacus 
internus muscle, to which, and to the quadratus lumborum, it dis- 
tributes branches: it also sends ramifications into the spinal cavity, 
and anastomoses with the lower lumbar arteries ; sometimes it sup- 

* Anat. Atlas, Figs. 469 to 472, inclusive. 



INTERNAL ILIAC ARTERY, AND ITS BRANCHES. 265 

plies the place of the last lumbar entirely. The inferior branch 
going outwardly, is divided into two orders of ramifications which 
supply the iliacus internus muscle, on its surface and more deeply ; 
also the os ilium by a ramuscule which penetrates the nutritious fora- 
men of the latter. The inferior branch anastomoses with the cir- 
cumflexa ilii of the external iliac. 

The Lateral Sacral Arteries (Jlrterice Sacra Lateraks) arise next, 
either from the hypogastric or from its posterior trunk : their number 
is commonly equal to that of the foramina on the side of the sacrum in 
front, though they may come from only one or two roots. They 
cross in front of the sacrum, and divide into branches, some of which 
anastomose with the middle sacral artery, while others enter the 
foramina of the sacrum, to be spent on the lower part of the cauda 
equina. 

The Obturator Artery (Arteria Obturatoria) comes commonly from 
the hypogastric or from one of its principal trunks ; in some cases it 
arises from the epigastric or from the external iliac, near Poupart's 
ligament. In the first cases it passes forwards parallel with the 
brim of the pelvis, and in the latter cases it descends behind the 
superior ramus of the pubes. Whatever may be the condition of its 
origin, it gets from the pelvis through the upper part of the thyroid 
foramen over the superior margin of the obturator internus muscle, 
having previously sent off some inconsiderable ramifications to 
the periosteum and the contiguous muscles within the pelvis. 

It emerges from the pelvis on the upper margin of the obturator 
externus muscle, and then divides into two principal trunks. The 
posterior descends along the external margin of the obturator ex- 
ternus muscle, to which it gives ramifications ; it likewise sends 
some branches to the heads of the muscles coming from the tuber 
of the ischium, and thereby anastomoses with the sciatic artery : 
other branches are spent upon the hip joint, one of which gets into 
the cavity of the latter through the notch at the lower part of the 
acetabulum, and is spent upon the adipose matter in its bottom. 
The anterior branch goes to the heads of the adductor muscles, to 
the pectineus, to the obturator externus, and to the integuments of 
the upper internal part of the thigh. Near its origin this branch 
sends a ramification along the internal margin of the thyroid fora- 



266 CIRCULATORY SYSTEM. 

men to anastomose with the posterior branch, so that the foramen, 
is surrounded by an arterial circle. 

The Middle Haemorrhoidal Artery (Art. Hcemorrhoidea Media) 
varies in its origin, being sometimes from the hypogastric itself and, 
on other occasions, from one of its branches, as the gluteal, ischiatic, 
&c. It descends on the fore part of the rectum, opposite the 
lower fundus of the bladder in the male, and is distributed by 
branches to the rectum, to the vesicula seminalis, and to the pros- 
tate gland. In the female it dispenses branches to the vagina. It 
is called middle, from its position between the upper and the lower 
haemorrhoidal arteries. 

In both sexes, the branches which it sends to other parts besides 
the rectum, frequently arise from other arteries, and in a man- 
ner which causes them to have distinct appellations, as vaginal, &c. 

The Vesical Arteries (Arteries Vesicates) consist in several rami- 
fications, corning from what was the umbilical artery of the foetus, 
but which, in the adult, with the exception of a short space near its 
origin, is converted into a ligamentous chord. These branches 
ramify upon the parietes of the bladder ; one of them more volumi- 
nous than any other, and called, by M. Chaussier, vesico-prostatic, 
gains the lower fundus of the bladder; sends branches to it, to the 
prostate, to the vesicula seminalis, and to the commencement of the 
urethra. 

The Uterine Artery (Arteria TJterina) arises from the hypogastric, 
or one of its branches, near the vesical, sometimes before, and on 
other occasions subsequent to them. Being peculiar to the female 
sex, its size varies according to the individual being in a state of 
pregnancy or not : in the latter stages of gestation it is as large as 
any other branch of the hypogastric. 

It goes inwards towards the superior part of the vagina, to which 
it gives some ramifications ; it then ascends between the laminae of 
the broad ligament, in a tortuous manner along the side of the uterus, 
and divides into many branches which are distributed through the 
tissue of this organ. It anastomoses with the corresponding arteries 
of the other side, and with the branches of the spermatic artery which 
go to the Fallopian tube and to the ovarium. 

Besides the preceding, the Hypogastric, or Internal Iliac artery 



INTERNAL ILIAC ARTERY, AND ITS BRANCHES. 267 

sends off two large branches, the Gluteal and the Ischiatic, which 
terminate it. In many subjects they are the direct continuation of 
the two primitive trunks, into which the hypogastric is frequently 
originally divided. 

The Gluteal Artery, {Arteria Glutea,) shortly after its origin, 
issues from the pelvis above the pyriformis muscle, at the upper part 
of the ischiatic foramen, where it adheres closely to the edge of the 
bone. When it first gets to the dorsum of the ilium, it is covered 
by the gluteus magnus muscle, and lies at the posterior margin of 
the gluteus minimus, precisely under a line drawn from the posterior 
superior spinous process to the top of the trochanter major. It 
almost immediately afterwards divides into two principal trunks. 

One of these trunks, the more superficial, advances between the 
gluteus medius and the magnus, and distributes branches to them ; 
also, to the posterior margin of the magnus, where it comes from 
the posterior sacro-sciatic ligament. The more deeply-seated trunk 
goes forwards between the gluteus medius and minimus, and sub- 
divides into three orders of branches for their supply. One set 
follows the superior margin of the gluteus minimus towards the 
anterior superior spinous process; another set passes nearer the 
middle of the gluteus minimus; and the third set still lower down ^ 
upon the dorsum of the ilium, above the acetabulum; some of the.' 
ramifications go to the capsular ligament of the joint, where they 
anastomose with branches from the femoral artery. 

The Ischiatic Artery {Arteria Ischiadica) is somewhat smaller than 
the gluteal, but looks rather more like the continuation of the hypo- 
gastric. It descends between the rectum and the pyriformis muscle, 
and issues under the lower margin of the latter, out of the pelvis, 
being there placed in front of the sciatic nerve. It goes downwards 
on the back of the thigh, between the trochanter major and the 
tuberosity of the ischium, being at the internal edge of the sciatic 
nerve, and on the posterior face of the small rotator muscles of the 
thigh. It sends off in the pelvis the internal Pudic Artery, and also 
some inconstant branches, of small size, to the viscera within the 
pelvis; when it has emerged from the latter, it detaches some con- 
siderable branches to the origin and to the inferior margin of the 
gluteus magnus muscle, and to the small rotator muscles. The 
branch which may be considered as the continued trunk of the 



268 CIRCULATORY SYSTEM. 

ischiatic, descending on the posterior face of the thigh, along with 
the sciatic nerve, under the hamstring muscles, is lost in ramifica- 
tions to them, and by anastomoses with the perforating arteries. 

The Internal Pudic Artery,* (Arteria Pudica Interna,) though a 
branch of the ischiatic, is only in a slight degree smaller. It arises 
a little above the spinous process of the ischium, in the pelvis, in 
front of the sciatic plexus, and getting from the pelvis between the 
anterior sacro-sciatic ligament and the inferior margin of the pyri- 
formis muscle, it passes over the posterior face of the anterior sacro- 
sciatic ligament, at the spinous process of the ischium. It imme- 
diately afterwards returns into the cavity of the pelvis, between the 
two sacro-sciatic ligaments, at the place where the obturator internus 
muscle winds over the ischium; it then goes along the internal face 
of the latter bone and of its ascending ramus, at the inferior margin 
of the obturator internus muscle ; and continues on the internal face 
of the ramus of the pubes, between the two laminae of the triangular 
ligament, above the cms of the penis to the symphysis of the pubes. 

In this course the Internal Pudic Artery detaches several impor- 
tant branches, in the following order : — 

a. A ramification along the inferior margin of the pyriformis, to 
this muscle and to the parts on the posterior face of the neck of the 
os femoris, where it anastomoses with the other arteries of this re- 
gion. 

b. The Lower Haemorrhoidal Artery {Art. Hamorrhoidea Inferior, 
Externa) to the inferior part of the rectum, and to the external 
sphincter ani muscle. This artery arises after the internal pudic 
has returned within the pelvis, and consists sometimes in several 
branches. 

c. The Perineal Artery [Art. Perinea, Transversa Perinei) has 
its root near the origin of the transversus perinei muscle, and ad- 
vancing obliquely forwards is distributed in several ramifications to 
the muscles and integuments of the perineum, and to the posterior 
part of the scrotum. It is unavoidably cut in the lateral operation 
for the stone. In the female it goes to the sphincter vaginas and to 
the labium externum. 

d. When the internal pudic has got beyond the transversus peri- 
nei muscle near the beginning of the crus penis, it detaches to the 

* Anat. Atlas. Figr. 467. 



EXTERNAL ILIAC ARTERY, AND ITS BRANCHES. 



269 



bulb of the urethra, along the posterior margin of the triangular liga- 
ment, a branch which penetrates to the corpus spongiosum, and is 
minutely distributed upon it, some of its ramifications reaching to 
the corpus cavernosum. This branch is called by M. Chaussier, 
Urethro-bulbar, and instead of being always distinct, it on some oc- 
casions comes from the Perineal. 

e. At the under part of the symphysis pubis, between it and the 
back of the penis, the internal pudic sends forwards, on the dorsum 
of the penis, a superficial branch, (Ramus Superficialis Dorsi Penis.) 
It advances to the end of the penis, under the skin, being parallel 
with its fellow of the other side, and near to it : sometimes the two 
unite after a short course. They are dispersed in branches to the 
integuments, and to the elastic ligament of the penis. 

f. The Cavernous Artery of the Penis (Art. Cavernosa Profunda 
Penis) may be considered as the terminating trunk of the internal 
pudic. It penetrates the corpus cavernosum, beneath the symphy- 
sis of the pubes, and quickly divides into many ramifications. The 
latter advance, and continue to subdivide upon the cells of the 
corpus cavernosum, to which they are principally distributed : some 
of them reach the corpus spongiosum urethrse, and others anastomose 
with the corresponding arteries of the other side. 



SECT. VIII. — OF THE EXTERNAL ILIAC ARTERY, AND 
ITS BRANCHES.* 

The External Iliac Artery (Arteria Iliaca Externa) extends from 
the bifurcation of the primitive iliac to Poupart's ligament, where it 
is continued to the lower extremity under the name of the femoral 
artery. It looks like the continuation of the primitive iliac, and de- 
scends at the superior strait of the pelvis along the internal margin 
of the psoas magnus muscle. In the early part of its course, it is 
anterior to the external iliac vein ; it then, as it approaches Poupart's 
ligament, gets to its outer margin. It is covered by the peritoneum 
in front. Where it passes beneath Poupart's ligament to the thigh, 
it is about half way between the anterior superior spinous process of 
the ilium and the symphysis pubis, having the vein at its pubic 
margin and the anterior crural nerve, half an inch from its iliac 

* Anat. Atlas, Figs. 466, 468. 
Vol. II.— 24 



270 CIRCULATORY SYSTEM. 

margin. No branches of consequence arise before it reaches the 
crural arch ; it then sends of two, the Epigastric and the Circumflex 
Iliac Artery. 

The Epigastric Artery [Jhteria Epgastrica) arises somewhat 
above the crural arch, at the line where the peritoneum is reflected 
from the fascia transversalis upon the iliac fascia. It at first passes 
horizontally inwards, then rises obliquely upwards and inwards, be- 
hind the spermatic chord, at the pubic margin of the internal abdo- 
minal ring. Afterwards it reaches the external margin of the rectus 
abdominis muscle, two or three in: hes above the pubes: ascending 
along it for a short distance, it then passes to its posterior face, and 
continues ascending above the umbilicus; where being divided into 
several branches, it terminates by anastomosing with the lower ra- 
mifications of the internal mammary artery. 

This artery is almost entirely spent upon the anterior parietes of 
the abdomen, in ramifications, which anastomose with the last in- 
tercostals and with the lumbar arteries. One of its small twigs, 
called the External Spermatic artery, following the course of the 
spermatic chord, or of the round ligament, is distributed upon the 
cremaster, the tunica vaginalis, and the scrotum of the male, and 
upon the mons veneris of the female. In some cases the epigastric 
gives off the obturator artery as stated. 

The Circumflex Iliac Artery {Arteria Circumflexa Ilii) is of the 
same size with the epigastric, and comes from the external iliac, 
sometimes on a level with it, and on other occasions low T er down, 
even below the crural arch. It ascends outwardly towards the an- 
terior superior spinous process of the ilium, along the posterior mar- 
gin of the crural arch, and following afterwards the direction of the 
crista of the ilium, it anastomoses with the corresponding branch of 
the ilio-lumbar artery. 

The following branches come from it. In the early part of its 
course some important twigs are sent to the adjacent muscles, as the 
sartorius, iliacus internus and so on. At the anterior superior 
spinous process, it divides into two branches; the smaller ascends 
between the internal oblique and the transversalis muscle, and is 
distributed upon them ; the other branch which is the continuation 
of the main trunk along the crista of the ilium at the margin of the 
iliacus internus muscle, sends ramifications to the latter, and also 



FEMORAL ARTERY, AND ITS BRANCHES. 271 

to the posterior part of the broad muscles of the abdomen, where it 
anastomoses with the other arteries of this region. 



Of the Femoral Artery* 

The Femoral Artery (Arteria Femoralis, Cruralis,) the continua- 
tion of the external iliac, extends from the crural arch or Poupart's 
ligament, to a perforation for its passage through the adductor mag- 
nus muscle, and which is commonly one-third of the whole length 
of the os femoris, above the knee joint. This great trunk, imme- 
diately below Poupart's ligament is very superficial, and may be 
felt pulsating where it passes over the pubes. It is there covered 
only by the common integuments, and the fascia femoris, which is 
thin ; it is bounded internally by the femoral vein, externally by the 
crural nerve ; is half-w r ay between the anterior superior spinous pro- 
cess and the symphysis of the pubes, and lies upon the internal 
face of the psoas magnus over the interstice between it and the 
pectineus. In the upper third of its course the femoral artery is at 
the inner edge of the rectus femoris, and at a short distance from it ; 
it then inclines inwards, and occupies the angle formed by the ad- 
hesion of the vastus internus to the adductor longus. The sartorius, 
at first, is remote at its outside, but this muscle, inclining inwards in 
its descent gets to the exterior margin of the artery, and afterwards 
covers it completely for the remainder of its course. The femoral 
artery is in front of the femoral vein when it has descended three 
or four inches below the crural arch ; behind the two is the arteria 
profunda. When the femoral artery and vein reach the angle 
formed by the vastus internus and the adductor longus, they are 
covered by a strong interlacement of tendinous fibres from these 
muscles. 

The femoral artery sends off these branches : 

1. The Superficial Artery of the Abdomen (Art. ad Cutem Ab- 
dominis) is small, and arises at the lower margin of Poupart's liga- 
ment: it goes upwards towards the umbilicus, beneath the fascia 
superficialis abdominis, and is distributed to the integuments of this 
region. One of its ramifications goes to the inguinal glands. 

* Anat. Atlas, Figs. 466, 469. 



272 CIRCULATORY SYSTEM. 

2. The External Pudic Arteries {Art. Pudenda Externa) come 
from the femoral at the same point, and are two or three in number; 
they are of small size. One of them inclines inwards along the 
groin, between the skin and the fascia femoris, and is distributed 
to the integuments of the pubes, to those of the penis, and to the 
scrotum, or to the labium externum of the female. The second, and 
the third when it exists, are rather lower down, and are dispersed 
upon much the same region by branches to the integuments. The 
lymphatic glands of the groin also derive their supply of blood from 
these several external pudic arteries. 

3. The Profound Artery, {Arteria Profunda Femoris,) the great 
muscular artery of the thigh, is but slightly inferior in size to the fe- 
moral itself, and comes from the latter at the distance of from one or 
two inches below the crural arch. It lies behind the femoral artery, 
and descends in that situation between the insertion of the adductor 
brevis and the vastus internus muscle, to the upper part of the 
insertion of the adductor longus. In this course its size is much 
diminished by the origin from it of several considerable trunks as 
follows : 

a. The External Circumflex, {.Arteria Circumfiexa Externa,) 
though most frequently a branch of the profunda, sometimes comes 
from the femoral above or below it a short distance. It goes im- 
mediately outwards between the rectus femoris muscle and the cru- 
ralis, giving off some inconsiderable ramifications. While between 
these muscles it divides into two branches, one of which ascends 
and the other descends ; the former is distributed to the anterior 
margin of the gluteus medius and minimus, to the capsule of the 
joint, the parts about the trochanter major, and anastomoses with 
the gluteal and the ischiatic. It is said by Meckel, that these anas- 
tomoses have been found much dilated where the external iliac 
artery has been taken up. The descending branch is about the size 
of a crow quill, or even larger ; it first passes obliquely downwards 
between the rectus femoris and the cruralis, it then descends verti- 
cally under the anterior margin of the vastus externus, between it 
and the cruralis, to terminate at the knee, where it becomes super- 
ficial and anastomoses with the articular arteries. It is, however, 
principally distributed to the vastus externus and to the cruralis. 

b. The Internal Circumflex Artery {Arteria Circumjlexa Interna,) 
arises from the profunda, near the external circumflex, generally 



PROFOUND ARTERY, AND ITS BRANCHES. 273 

below it, but sometimes the reverse ; in some cases, it comes from 
the femoral artery itself, near the crural arch. It passes transversely 
inwards, and dips into the interstice between the pectineus and the 
psoas magnus, after having given off some small twigs to the heads 
of the adjoining adductors. It then winds under the neck of the os 
femoris and divides into two branches ; the upper one goes to the 
capsular ligament of the joint, to the obturator externus muscle, anas- 
tomoses with the obturator artery, and sends a branch behind the 
adductor brevis to the upper part of the adductor magnus : the inferior 
branch is larger than the other; it descends behind the adductor 
magnus and is distributed in branches to it, to the gracilis, and to 
the hamstring muscles, sending upwards some ramifications (rami 
trochanterici) to the parts about the trochanter major, where they 
anastomose with the external circumflex artery. 

c. Muscular branches of inconstant origin, and of inconsiderable 
size, are sent from the profunda to supply the anterior face of the ad- 
ductor muscles. 

d. The Perforating Arteries (Rami Profundi Perforantes) obtain 
the name from their perforating the adductor magnus, which they do 
near the linea aspera, so as to get to the back of the thigh. They 
commonly are four in number, and as they come off successively 
from the profunda, they are designated numerically. In some cases, 
however, they are reduced to one, by being concentrated in a com- 
mon trunk, which penetrating high up the adductor magnus, and 
afterwards descending on its posterior face, is dispersed upon the 
muscles on the back of the thigh. 

The First Perforating Artery arises somewhat below the trochanter 
minor, and penetrates the adductor magnus a little below its superior 
margin. One of its branches ascends towards the trochanter major, 
where it anastomoses with the external circumflex and with the 
gluteal, while another descending is spent upon the heads of the 
flexor muscles of the leg. 

The Second Perforating Artery gets to the back of the thigh, at 
the lower magin of the insertion of the gluteus magnus into the linea 
aspera, being distributed in that region, and to the corresponding 
portion of the long head of the biceps flexor cruris. 

The Third Perforating Artery penetrates the Adductor magnus 
somewhat below the commencement of the short head of the biceps, 
and is dispersed upon the adductor and the adjacent portion of the 
flexor muscles. 

24* 



274 CIRCULATORY SYSTEM. 

The Fourth Perforating Artery penetrates the insertion of the ad- 
ductor magnus an inch and a half above the opening in it, for the 
femoral artery ; it, in the same way, supplies the posterior face of 
the adductor and the adjacent muscles. 

As a summary, it will be readily understood that the profunda is, 
in this way, through the external and the internal circumflex, and 
through the perforating arteries, distributed upon all the large mus- 
cles of the thigh. 

After the origin of the profunda, the Femoral Artery gives off, at 
different points of its course to the opening of the adductor magnus, 
several twigs the size of a large knitting needle ; which go to the 
sartorius, the gracilis, the adductors and the extensors on the front 
of the thigh ; but they are too inconstant to require a more particular 
description. 

The Anastomosing Artery (Arteria Anasiomotica) is the last branch 
of the femoral, and arises just before it perforates the adductor mag- 
nus. It descends to the knee, in front of the tendon of the latter, 
concealed by the internal margin of the vastus internus muscle. It 
sends off many small twigs to the adjacent muscles, and terminates 
below by anastomosing with the internal articular arteries. It is 
about the size of a crow-quill. 

The Popliteal Artery {Mrteria Poplitcca)* is the continuation of the 
femoral, after the latter has passed through the tendinous insertion 
of the adductor magnus; and extends from this point to the opening 
in the interosseous ligament of the leg, just below the head of the 
tibia. It, first of all, passes from the internal margin of the os femo- 
ris, to the notch between the condyles ; being there placed in the 
middle between the internal and the external hamstring muscles, 
and surrounded by a mass of adipose matter which fills up the hol- 
low of the ham. It is in contact, anteriorly, with the knee joint, and 
a little below the latter with the popliteus muscle, descending there 
between the heads of the gastrocnemius. It is covered, in the greater 
part of its extent, posteriorly, by the popliteal vein, and by the sci- 
atic nerve, the latter being more superficial than the vein. 

The popliteal artery sends off some small branches to the haro- 

* Anat. Atlas, Figs. 471, 473. 



POPLITEAL ARTERY, AND ITS BRANCHES. 275 

string muscles, and to the parts contained between the latter, which 
are too irregular and inconstant for description. The following arte- 
ries, also, come from it : — 

1. The Superior Internal Articular Artery {Art. Articularis Supe- 
rior Interna) arises at or above the internal condyle, and frequently 
consists in two trunks. It passes through the tendon of the adductor 
magnus, just above the condyle ; it then begins to distribute itself in 
branches, some of which are spent upon the lower part of the vastus 
internus muscle, and others upon the superior internal part of the 
knee joint. 

2. The Superior External Articulating Artery {Art. Articularis 
Superior Externa) arises from the popliteal, somewhat above the 
external condyle of the os femoris. It winds, horizontally, above 
the external condyle, around the bone, between it and the lower 
part of the biceps flexor cruris, and is then distributed, also, in two' 
orders of branches, some of which supply the lower part of the vas- 
tus externus muscle, and others the superior external portion of the 
knee joint. 

3. The Middle Articular artery {Art. Articularis Media) is smaller 
than either of the above, and sometimes comes from one of them, but 
generally from the popliteal, on a line with the articulation of the 
knee. It is distributed to the posterior part of the capsular ligament, 
to the crucial ligaments, and to the corresponding adipose matter. 

4. The Inferior Internal Articular Artery {Art. Articularis Inferior 
Interna) arises on a line with the inferior part of the internal con- 
dyle, sometimes lower down. Its origin is very much concealed by 
the internal head of the gastrocnemius ; it passes beneath the latter, 
and then between the internal lateral ligament, of the knee and the 
head of the tibia; consequently, it is covered by the internal ham- 
string muscles. It afterwards ascends towards the patella, and is 
distributed in numerous branches to the inferior internal part of the 
knee joint, and to the adjacent portion of the tibia. 

5. The Inferior External Articular Artery {Art. Articularis Infe- 
rior Externa) arises near the last, below the external condyle, being 
concealed by the belly of the plantaris. It passes, horizontally, or 
nearly so, between the popliteus and the outer head of the gastroc- 



276 CIRCULATORY SYSTEM. 

nemius, and afterwards beneath the tendon of the biceps and the ex- 
ternal lateral ligament of the joint, around the external face of the 
head of the tibia. It gives small branches to these several parts, and 
is then distributed, by two orders of ramifications, to the superficial 
and to the more deeply seated parts at the external inferior portion 
of the knee joint. 

These several articular arteries anastomose freely with each 
other, and are minutely ramified on the knee joint and the contigu- 
ous structure. They also anastomose with the long descending 
branch of the external circumflex of the thigh, with the anastomotica 
of the femoral, and with the tibial recurrent. 

6. The Gastrocnemial Arteries [Arteries Gemellce) are two in 
number, one for each head of the gastrocnemius. They arise 
commonly between the superior and the inferior articular arteries, 
and are about the same size. They penetrate into the muscle, and 
supply it with blood, terminating their course near the lower part of 
its bellies. 

Moreover, some small branches, which go to the contiguous mus- 
eles, are frequently observed here ; also, the nutritious artery of the 
tibia. But their number and condition are very inconstant. Near 
the head of the fibula, branches go from the popliteal artery to the 
upper end of the soleus muscle. 

Generally, on a level with the aperture in the upper part of the 
interosseous ligament, but sometimes an inch or two higher up, the 
popliteal artery terminates by dividing into two large trunks, the 
Anterior and the Posterior Tibial. 

The Anterior Tibial Artery* (Art. Tibialis Anterior) passes for- 
wards through the foramen of the interosseous ligament, just below 
the head of the fibula, and runs down the front of the leg and foot, 
as far as the base of the metatarsal bone of the great toe. In this 
course, its relative situation is as follows : 

It rests upon the front of the interosseous ligament of the leg, on 
a line drawn from the middle anterior part of the head of the fibula 
to the middle of the ankle joint. Superiorly, it is bounded on the 
tibial side by the tibialis anticus muscle, and on the other by the 
extensor longus digitorum : lower down on the leg, the place of the 

* Anat. A-tlas, Fig. 471. 



ANTERIOR TIBIAL ARTERY, AND ITS BRANCHES. 277 

latter is supplied by the extensor pollicis pedis. Somewhat above 
the ankle joint the artery, leaving the interosseous ligament, rests 
upon the front of the tibia, and then gets to the top of the foot, be- 
tween the joint and the annular ligament. Under the ligament it is 
crossed by the tendon of the extensor pollicis, which gets to its in- 
ner side, and afterwards continues so. The anterior tibial nerve 
adheres to it, in its whole length. 

The following branches come from the anterior tibial artery : 

1. The Recurrent Tibial {Art. Tibialis Recurrens) ascends through 
the upper extremity of the tibialis anticus muscle, having come off 
from the anterior tibial immediately upon the latter getting to the 
front of the leg. Several small ramifications pass from it to the 
heads of the contiguous muscles on the tibia, and to the lower part 
of the knee joint, where it anastomoses with the lower articular 
arteries of the knee. 

2. Several small arterial twigs are afterwards sent to the mus- 
cles and to the periosteum of the leg, as the anterior tibial descends ; 
but they are too inconstant in size and position to require descrip- 
tion. 

3. The Internal Malleolar Artery [Art. Malleolaris Interna) arises 
from the anterior tibial, an inch or two above the ankle joint. It 
descends, inwardly, between the tibia and the tendon of the 
tibialis anticus, and, having gained the internal malleolus, is dis- 
tributed by branches upon it and upon the adjacent portion of the 
articulation. 

4. The external Malleolar Artery (j9rt. Malleolaris Externa) con- 
sists most commonly in two arterial twigs of small size, but frequently 
in one only. It arises in front of the ankle joint, and going out- 
wardly between it and the tendons of the extensor digitorum longus, 
is spent upon the external face of the articulation, where it inoscu- 
lates with the peroneal artery. 

This artery is sometimes of considerable size, in which case it 
also supplies the outer part of the tarsus, and is a substitute for the 
next. 

5. The Tarsal Artery (Arteria Tar sea) arises from the anterior 



278 



CIRCULATORY SYSTEM. 



tibial, somewhat below the ankle joint near the scaphoides, and y 
going outwardly beneath the extensor brevis digitorum muscle, it is 
distributed in branches near the external ankle, and upon the outer 
upper surface of the tarsus. It anastomoses with the external mal- 
leolar, with the external plantar, and with the metatarsal artery. 

Some small branches also pass from the anterior tibial at this point 
to the upper internal face of the tarsus. 

6. The Metatarsal Artery (Art. Metatarsea) arisesjust below the 
last. It is directed forwards and outwards beneath the extensor 
brevis muscle, and forms a sort of arch at the roots of the metatarsal 
bones. It furnishes several ramifications to the upper surface of the 
tarsus and the contiguous parts; amongst them is an interosseal 
artery for each of the three outer interosseal spaces. These arteries 
communicate, by small anastomoses, with the arteries of the sole of 
the foot, both at the bases and at the ends of the metatarsal bones, 
and terminate in front by supplying the backs of the small toes. 

This artery is sometimes a branch of the tarsal. 

7. The Dorsal Artery of the Great Toe (Art. Borsalis Hallucis) 
arises from the anterior tibial at the root of the first metatarsal bone. 
It runs along the superior face of the first metatarsal interval, and 
having reached the anterior end of it, divides into two branches, 
one of which goes to the back of the great toe and the other to the 
tibial margin of the next toe. 

The Anterior Tibial, in its course from the ankle joint to the base 
of the first metatarsal bone, is sometimes called Pedal (Arteria 
Pedicea;) at the posterior end of the first metatarsal interval, being 
still of considerable size, it sinks down to the sole of the foot, and 
joins itself to the external plantar artery at this point. 

It frequently happens that the anterior tibial being small in its 
course down the leg, is joined by the continued trunk of the pero- 
neal, which perforates the interosseous ligament somewhat above 
the ankle joint. Afterwards the trunk formed by this union, being 
of considerable size, follows the course and has the distribution 
mentioned. 

The Posterior Tibial Artery (Arteria Tibialis Posticu*) is some- 
* Anat. Atlas, Fig. 475. 



THE POSTERIOR TIBIAL ARTERY. 279 

times called, at its commencement, till it gives off the peroneal, 
tibio-peroneal ; it extends from the head of the tibia to the sinuosity 
of the os calcis, in a line from the middle of the ham to the internal 
ankle. It is at the tibial side of the back of the leg, on the posterior 
face of the flexor longus digitorum muscle; and covered by the 
fascia of the latter. In the two superior thirds of its course, it is 
concealed behind by the gastrocnemius and the solseus muscle: in 
the inferior third, it is at the internal margin of the tendo-achillis. 
At the ankle joint, before it passes into the sinuosity of the os calcis, 
it is between the tendon of the tibialis posticus and that of the flexor 
longus pollicis pedis, being covered by the laciniated ligament. 
It is accompanied, at its external margin, by the posterior tibial 
nerve. 

The posterior tibial artery is distributed after the following 
manner: 

1. The Peroneal Artery (Arteria Peronea) is its first branch of any 
importance, and is but little smaller than the continued trunk. It 
arises an inch or two below the origin of the anterior tibial, and 
extends, on the posterior face of the leg, to the external ankle. It 
is, in some measure, concealed by the posterior side of the fibula, 
being placed there between the origin of the flexor longus pollicis 
muscle and the external edge of the tibialis posticus. It is covered 
behind by the flexor longus pollicis, by the soleus, and by the gas- 
trocnemius; it is, therefore, deep and of extremely difficult access 
in the living body. 

In this course, it sends small branches to the gastrocnemius, to 
the soleus, and to the other contiguous muscles on the back of the 
leg. After having descended two-thirds of the length of the fibula, 
it divides into an anterior and a posterior branch. The former 
traverses the interosseous ligament, and descending in front of it, 
covered by the muscles which arise from the lower part of the 
fibula, is distributed upon the upper external part of the foot near 
the ankle joint. The posterior branch continues in the primitive 
course of the peroneal artery at the internal posterior margin of the 
fibula, and descending behind the tibio-peroneal articulation, 
reaches the external face of the os calcis: it detaches several small 
ramifications to the contiguous muscles; and, upon the os calcis, 
is divided into twigs which supply the adjacent parts and the integu- 
ments below the external ankle. 



280 



CIRCULATORY SYSTEM. 



2. In the descent of the posterior tibial artery to the hollow of 
the os calcis, it detaches several small muscular branches, princi- 
pally to the tibialis posticus, and to the flexors of the toes. One 
twig, which is the nutritious artery of the tibia, comes from its 
upper part when not furnished from the popliteal artery, and enters 
the foramen on the posterior surface of the bone. 

While the posterior tibial is in the hollow of the os calcis, be- 
tween it and the abductor muscle of the great toe, it furnishes some 
small twigs to the contiguous muscles, and to the integuments of 
the sole of the foot ; it then divides into two branches, the Internal 
and the External Plantar Artery.* 

The Internal Plantar Artery (Art. Plantaris Interna) is much 
smaller than the other. It advances between the abductor pollicis 
pedis and the internal inferior margin of the bones of the foot, and 
terminates at the anterior end of the first metatarsal bone, by join- 
ing the internal digital artery of the great toe. In this course, it 
sends continually, small ramifications to the muscles of the great toe 
and to the flexor brevis digitorum pedis. One of the largest of these 
ramifications comes off near the os scaphoides, and cruises along 
the internal margin of the abductor pollicis to its anterior end ; 
another becomes superficial on the sole of the foot, between the ab- 
ductor pollicis and the flexor brevis digitorum, and goes forward as 
far as the other. 

The External Plantar Artery (Art. Plantaris Externa) is the con- 
tinuation of the posterior tibial, and diverges from the internal 
plantar towards the outer margin of the sole of the foot, between the 
flexor brevis digitorum pedis and the flexor accessorius. Having 
reached the internal margin of the abductor minimi digiti, it ad- 
vances along the latter to the base of the metatarsal bone of the 
fourth toe ; it then makes a curvature forwards and inwards across 
the metatarsal bones, between the tendons of the flexor longus digi- 
torum and the interosseous muscles, to the first metatarsal interval, 
where it is joined by the anterior tibial artery from above. This 
curvature is the Arcus Plantaris, of which the concavity is behind 
and inwards. 

The external plantar artery is distributed as follows : — 

* Anat. Atlas, Figs. 476 to 479, inclusive. 



POSTERIOR TIBIAL ARTERY, AND ITS BRANCHES. 281 

Shortly after its origin, it detaches a branch which goes backwards 
and outwards, and which keeping close to the os calcis in front of 
its tuberosity, is distributed to the heads of the muscles arising from 
it, and to the outer surface of the heel; it also sends an arteriole 
along the external edge of the abductor minimi digiti. 

At the base of the fourth metatarsal bone arises a branch called 
the External Digital Artery of the Little Toe. It goes at first deeply 
along the internal margin of the muscles situated on the fifth meta- 
tarsal bone, and, afterwards, at the head of the latter, it gets between 
them and the bone, and is distributed along the external margin of 
the little toe. 

The four Digital Arteries of the foot arise next successively from 
the arcus plantaris, at or near the metatarsal intervals. They run 
along the inferior surface of the interosseous muscles, getting to the 
bases of the first phalanges above the transversalis pedis. Each 
artery there bifurcates, so as to supply the opposed surfaces of the 
adjacent toes, in the same way that the digital arteries of the hand are 
distributed. 

The digital artery of the first metatarsal interval which comes from 
the internal extremity of the arcus plantaris, where the anterior 
tibial artery joins the latter, goes forwards concealed by the flexor 
brevis of the great toe: just behind the sesamoid bones, it sends a 
branch which supplies the internal side of the great toe, being its in- 
ternal digital artery, and anastomoses with the internal plantar artery. 
What remains of it, iskstill a trunk of considerable magnitude, which 
advancing to the space between the first phalanx of the great toe 
and of the toe next to it, there bifurcates, as mentioned, so as to 
supply the opposite sides of these two toes. 

The Perforating Arteries, as they are called, are of two kinds, the 
anterior and the posterior. The former arise from the convexity of 
the plantar arch and being destined principally to the interosseous 
muscles, anastomose at the anterior end of the latter with the 
branches from the metatarsal artery, which supply their superior 
surface. The posterior perforating arteries come also from the 
plantar arch, and penetrating the posterior end of the interosseous 
spaces, anastomose also with the metatarsal arteries on the dorsum 
of the foot. 

The preceding trunks of the internal and of the external plantar 
Vol. II.— 25 



282 CIRCULATORY SYSTEM. 

arteries are the principal ones which are found in the bottom of 
the foot, but from them there arise an immense number of arte- 
rioles ; which, descending vertically between the interstices of the 
muscles and of the aponeurosis plantaris, supply the adipose matter 
and the skin of the sole of the foot, so as to render them extremely 
vascular. 



CHAPTER III. 



Of the Veins. 



The veins of the body, assembling from differing points, unite 
successively into the ascending and into the descending vena cava, 
which discharge their blood into the right auricle of the heart. The 
veins of the head, of the upper extremities, and of the thorax, run 
into the descending cava, while the veins of the abdomen and of the 
lower extremities concur to form the ascending cava. 



SECT. I. — OF THE VEINS OF THE HEAD AND NECK.* 

Many of these veins are described elsewhere with the encephalon 
and with the eye, to which accounts the reader is referred. The 
others are more superficial, and arise as follows : 

The Facial Vein (Vena Facialis) observes the course of the 
facial artery, being placed behind the latter. It arises upon the 
forehead by a considerable number of roots, which unite into a 
single trunk called the frontal vein. This vein descends from the 
forehead, over the root of the nose, along the internal canthus of 
the orbit. It there receives re-enforcements from the eyelids, and 
anastomoses with the ophthalmic veins ; descending afterwards, in 
the same way with the facial artery, and taking the name of facial 
vein, it receives successively the veins from the nose, from the outer 

* Anat. Atlas, Figs. 480, 481, 482. 



OF THE VEINS. 483 

side of the orbicularis palpebrarum, from the upper and lower lips, 
and from the muscles and the integuments of the face. It descends 
to the neck at the anterior margin of the masseter muscle, and is 
then augmented by the ranine, the submental, and the inferior pala- 
tine veins, and immediately afterwards goes into the internal or the 
external jugular vein. 

The Ranine Vein ( Vena Ranina) arises at the point of the tongue, 
and then goes along its under surface, where it can be readily seen 
by turning up the end of the tongue. It joins the facial near the 
posterior margin of the mylo-hyoideus muscle. 

The Submental Vein [Vena Submentalis) arises by ramuscules from 
the sublingual and the submaxillary gland, and from the contiguous 
muscles. It joins the facial vein a little below the last : sometimes 
it runs into the superior thyroidal vein. 

The Inferior Palatine Vein ( Vena Palatina Inferior) arises princi- 
pally from the soft palate and from the tonsil gland, but receives 
a few twigs from the contiguous parts. It corresponds with the in- 
ferior palatine artery, a branch of the dorsal lingual, (Dorsalis Lin- 
gua3 ;) and descends the pharynx along side of it, and terminates in 
the trunk of the facial near the last. 

The Lingual Vein ( Vena Lingualis) has its origin from a plexus of 
veins situated on the root of the tongue under its lining membrane, 
between the epiglottis and the foramen caecum : branches are' also 
sent to it from the muscular structure of the tongue, from the sublin- 
gual gland and from the adjacent muscles, and it anastomoses with 
the vena ranina. It goes backwards between the hyoglossus and 
the mylo-hyoideus muscle, along the superior margin of the os 
hyoides, and then discharges into the internal jugular vein near the 
facial. 

The Pharygeal Vein (Vena Pharyngea) arises from a plexus of 
veins belonging to the pharynx, and discharges either into the lingual 
or into the internal jugular near it. 

The Superior Thyroid Vein (Vena Thyroidca Superior) corre- 
sponds with the distribution of the superior thyroid artery, in the 



484 



CIRCULATORY SYSTEM. 



origin of its primitive roots. Having collected the latter into one 
or more trunks, it passes upwards and backwards beneath the 
sterno-hyoid and thyroid muscles, and discharges itself into the 
upper part of the internal jugular, or into one of the large branches 
of the external jugular. 

The Occipital Vein (Vena Occipitalis) arises from the branches 
of the occipital artery, and following the course of the latter, be- 
neath the muscles connected with the mastoid process of the tem- 
poral bone, it is discharged into the upper part of the internal jugu- 
lar or of the external ; more rarely into the latter. 

The Diploic Veins ( Vena Diploicce) have been described in the 
account of the bones of the cranium as situated between the two 
tables in the diploic structure, and commence by very fine capillary- 
tubes from its lining membrane. The one in the frontal bone dis- 
charges itself into the frontal vein, that in the occipital bone into the 
occipital vein, and the two in the parietal bone into the deep tem- 
poral veins. They do not open each by one orifice, but by several, 
which make their terminations not very distinct or abrupt : besides 
which, they communicate freely by a crowd of ramuscules, with the 
veins of the scalp on the outside, and with those of the dura mater 
internally. 

The Superficial Temporal Vein (Vena Temporalis Superficialis) 
corresponds with the temporal artery, and takes its rise from the 
terminating ramifications of the latter. It is immediately below the 
skin. Its branches communicate freely with each other, and with 
the branches of the frontal and of the occipital vein: at the zygoma 
it receives the trunk of the Middle Temporal Vein, which, collecting 
the blood from the temporal muscle and other parts within the 
zygoma, perforates the temporal fascia to discharge itself into the 
superficial temporal vein. 

The Temporal Vein, (Vena Temporalis,) which is formed by the 
junction of the Middle and the Superficial Temporal, descends over 
the root of the zygoma, in company with the artery, and penetrates, 
like the latter, through the substance of the parotid gland. It is 
joined, near the neck of the lower jaw, by the internal maxillary 
vein. It is also joined, in its descent through the parotid gland, by 



VEINS OF THE HEAD AND NECK. 285 

the anterior auricular veins, by the parotid veins, and by the trans- 
verse facial, all of which correspond with the arteries of the same 
name. The temporal vein, on issuing from the parotid gland, im- 
mediately afterwards becomes the External Jugular ; but, occasion- 
ally, it ends wholly, or in part, in the Internal Jugular. 

The Internal Maxillary Vein (Vena Maxillaris Interna) is derived 
from the terminating ramifications of all the arteries into which 
the internal maxillary is divided; it is, therefore, composed of the 
spheno-palatine vein, which brings the blood from the nose, of the 
infra-orbital, of the pterygoids, inferior maxillary, deep-seated tem- 
poral, and so forth, with the exceptions of the vein, which might 
belong to the middle artery of the dura mater, but which does not 
exist according to Portal and to Hippolytus Cloquet. By the aid 
of the spheno-palatine vein, the internal maxillary communicates 
with the sinuses in the bottom of the cranium, by branches, called 
the Emissary Veins of Santorini,* which pass through the foramen 
ovale, rotundum, and spinale. It also communicates with the plexus 
of veins on the side of the pharynx. 

The External Jugular Vein ( Vena Jugularis Externa) is generally 
the continuation of the temporal. It descends on the neck almost 
vertically, between the platysma myodes and the sterno-mastoideus, 
in the direction of the fibres of the first, and crossing those of the 
latter obliquely. Just behind the clavicle, at the external margin of 
the sterno-mastoideus, it opens into the subclavian vein, in front of 
the scalenus anticus muscle. Sometimes, instead of one trunk only, 
there are two or three, which unite at a variable distance above the 
subclavian. This vein varies also in its size, and in the branches 
from which it is made up : sometimes it receives the facial vein, and 
on other occasions the latter runs, as stated, into the internal jugular. 
The condition and arrangement of the internal and external jugulars 
are, indeed, so inconstant, in regard to the trunks that compose 
them, that it is scarcely possible to give more than a very general 
description of them with tolerable accuracy. 

The external j.ugular, in going down the neck, anastomoses more 
or less with the internal jugular, either directly or by its branches: 
one of these anastomoses is found near the angle of the lower jaw, 
about the trunk of the facial vein, and is so large as to explain the 

* Obs. Anat. chap. iii. p. 74. 
25* 



286 



CIRCULATORY SYSTEM. 



difference of opinion among anatornisls in regard to the latter's ter- 
mination. Sometimes the occipital vein, or a large trunk from it, 
joins the external jugular. At the lower part of the neck, the ex- 
ternal jugular is augmented by the superficial cervical veins. Some 
of these come from the lower part of the neck, near the shoulder, 
and join the jugular just above the clavicle; others are placed on 
the lower front part of the neck, above the sternum, and there form 
with each other a remarkable and an irregular plexus, consisting in 
numerous meshes. It frequently happens that the external jugulars 
of the two sides, just before they terminate, anastomose with each 
other by a large horizontal trunk, which runs just above the end of 
the sternum, in front of the sterno-mastoid, sterno-hyoid, and the 
sterno-thyroid muscles : this trunk, on other occasions, goes more 
deeply, and behind these muscles, from one subclavian vein to 
another, or to a jugular ; its mode of attachment is, indeed, much 
varied: when it exists, however, it frequently receives several of the 
superficial veins of the neck, and the inferior thyroideal. 

The Internal Jugular Vein (Vena Jugularis Interna) extends 
from the basis of the cranium to the internal margin of the first rib, 
at the insertion of the scalenus anticus muscle. The lateral sinuses 
of the dura mater, receiving ultimately all the blood of the brain, of 
the eye, and a portion of that of the nose, convey it from the cra- 
nium through the posterior foramina lacera; where they are joined to 
the upper end of the internal jugular veins, the lining membrane of 
each sinus being continuous with that of its respective vein. Each 
vein is somewhat enlarged at its commencement, which is therefore 
called its Gulf or Sinus ; the right vein is frequently larger than the 
left. The internal jugular then descends in front of the transverse 
processes of the vertebras of the neck, on the outer side of the inter- 
nal and of the primitive carotid artery, and of the pneumogastrie 
nerve. It is concealed above by the styloid process of the temporal 
bone, and the muscles belonging to it; it is crossed half vvay down 
the neck, by the omo-hyoideus muscle ; and, in the greater part of 
its course, is beneath, and nearly parallel with the anterior edge of 
the sterno-mastoideus. Having got behind the sternal end of the cla- 
vicle, it is joined at the internal edge of the scalenus anticus by the 
subclavian vein, and the union of the two forms the vena inno- 
minata. 

The internal jugular receives frequently the large anastomotic 



VEINS OF THE HEAD AND NECK. 287 

branch, just alluded to, from the external jugular, at the under mar- 
gin of the parotid gland, between the digastric muscle and the 
lower jaw, and it is in this vicinage that it is generally re-enforced 
by the Occipital ; the Lingual ; the Facial ; the Pharyngeal ; and 
the Superior Thyroidal Veins, that have been described. 

The Vena Innominata, or Brachio Cephalic Vein is the trunk 
formed on either side by the junction of the subclavian with the 
internal jugular. On the right side it looks like the continuation of 
the internal jugular, and descends in contact with the right pleura, 
behind the right side of the sternum, for the distance of an inch or 
thereabouts. On the left side it crosses behind the superior end of 
the sternum, descending obliquely in this course, from left to right, 
until it joins the trunk on the right side. It lies in front of the great 
vessels proceeding from the arch of the aorta; and is much longer 
than the trunk of the other side. A common name for it is the 
Transverse Vein. 

The Vena Cava Superior, or Descendens, arises from the junction 
of the two vense innominata?. It begins between the cartilage of the 
first rib on the right side, and the arch of the aorta, and descends to 
the superior posterior part of the right auricle, into which it empties 
itself. Its course is not entirely vertical, but inclining somewhat to 
the left side and forward. It is about three inches long. The supe- 
rior third of it is free, and is in contact on the right with the pleura, 
and on the left with the arteria innominata ; the remaining portion 
of it is invested by the pericardium, and has the aorta on its left an- 
terior face.* 

The following venous trunks discharge into the vena? innominata;, 
or into the descending cava. The Inferior Thyroidal ; the Verte- 
bral ; the Superior Intercostal ; the Internal Mammary ; the Vena 
Azygos, and some others of smaller size. 

1. The Inferior Thyroid Vein (Vena Thyroidea Inferior) arises 
from the inferior part of the thyroid gland, by many small roots, 
which anastomose with those of the opposite side. It descends in 
front of the trachea, involved in the loose cellular and fatty matter 

* In some very rare cases there have been two descending vense cavae, one 
for the right side and the other for the left. J. F. Meckel. 



288 CIRCULATORY SYSTEM. 

lying upon it, and empties itself into the left brachio-cephalic vein, 
or Transverse Vein. 

There is occasionally another thyroid vein, called the middle, 
which discharges itself into the lower part of the internal jugular. 

2. The Vertebral Vein (Vena Vertebralis) is placed in the same 
canal with the vertebral artery. At its upper extremity it anasto- 
moses with the occipital sinus, by a branch lodged in the posterior 
condyloid foramen. In its descent of the canal of the transverse 
processes, it communicates at each intervertebral foramen with the 
vertebral sinuses, and also receives a branch from the muscles of 
the neck. It issues at the sixth transverse process, and going on 
the right side behind the subclavian artery, but on the left, in front 
of it, is finally emptied into the commencement of the vena in- 
nominata. 

3. The Superior Intercostal Vein (Vena Intercostalis Superior) is 
on the right side an inconsiderable trunk, sometimes deficient, 
which commences by branches belonging to the first two intercos- 
tal spaces, and empties into the vena innominata just below the 
vertebral. On the left side it is much larger, and arises from the 
six or eight superior intercostal spaces. It lies on the left side of 
the bodies of the upper dorsal vertebra?, and at each intercostal 
space, as it ascends, receives its contribution of an intercostal vein, 
corresponding with the intercostal artery ; it also receives branches 
from the oesophagus, and about the third dorsal vertebra the left 
bronchial vein is discharged into it. Issuing from the thorax above, 
it discharges into the left vena innominata near its commence- 
ment. 

4. The Internal Mammary Vein (Vena Mammaria Interna) 
arises from the terminating branches of the internal mammary ar- 
tery, and in its situation and course corresponds with the latter. It 
is re-enforced by small branches from the diaphragm, the pericar- 
dium, and the thymus gland. Each internal mammary vein dis- 
charges itself on its respective side into the vena innominata near 
the superior intercostal. 

5. The Vena Azygos* is placed in the posterior mediastinum, 

* Anat. Atlas, Figs. 489, 490. 



VEINS OF THE HEAD AND NECK. 289 

on the right anterior margin of the Dorsal Vertebras, and dis- 
charges itself in making an arch forwards over the root of the 
right lung, into the descending cava, just above the introduction of 
the latter into the pericardium. Its orifice there is supplied with a 
membranous duplicature or valve, which prevents the blood once 
discharged from re-entering it. The valve is sometimes double, 
and also somewhat removed from the orifice. It was the observa- 
tions of these valves, first of all, which called the attention of Syl- 
vius and of Charles Etienne to their existence in other veins. 

This vein begins in the abdomen, either by an anastomosis with 
the ascending cava, or w T ith the upper lumbar vein; it then ascends 
into the 'thorax through the aortic orifice of the diaphragm, and 
continuing to mount upwards beneath the pleura it lies on the right 
side of the thoracic duct, and crosses in front of the intercostal 
arteries of the right side. In this course, it receives from the ten 
inferior intercostal spaces of the right side, their respective inter- 
costal veins corresponding in their origin and course with the in- 
tercostal arteries. About the sixth vertebra of the back, it receives 
a trunk ( Vena Hemiazygos) which is formed from the four or six 
lower intercostal veins of the left side, and commences in the ab- 
domen, also by anastomosis with the left emulgent vein or the left 
superior lumbar, and which gets into the thorax either through the 
aortic orifice of the diaphragm, or through, a special opening to 
the left of it. The vena azygos also receives some small ramifica- 
tions from the oesophagus, and near the fourth dorsal vertebra, the 
right bronchial vein is discharged into it. Other small ramifica- 
tions join it from the parietes of the descending cava, of the aorta, 
and of the right pulmonary artery. Branches also proceed to it, 
or to the intercostal veins from the interior of the vertebral canal 
at each intervertebral foramen. 

This vein is commonly spoken of by anatomists, as forming a 
great anastomosis between the ascending and the descending cava. 
The tendency to establish this anastomosis is strikingly confirmed 
by a preparation made by myself, when I was a student in this 
institution in 1813 ; and now in the Anatomical Cabinet. In it the 
ascending cava, instead of emptying, as usual, into the lower part 
of the right auricle, ascends on the right side of the dorsal verte- 
bree, and supplanting in situation and office the vena azygos, dis- 
charge itself into the descending cava, in a manner corresponding 



^® CIRCULATORY SYSTEM. 

with the vena azygos, by making a curvature forwards over the 
root of the right lung. 

The Sinuses of the Vertebral Column* (Sinus Column® Verte- 
bralis) are situated in the vertebral cavity, on the posterior face of 
the bodies of the vertebra, and in front of the dura mater of the 
spinal marrow. They are two long veins, one at each margin of 
the posterior vertebral ligament, and extend from the foramen mag- 
num occipitis to the inferior end of the sacrum. They are main- 
tained in their places by a loose cellular tissue between the bones 
and the dura mater, and therefore, unlike the sinuses of the brain, 
are entirely independent of the dura mater. 

These sinuses are small where they begin in the sacrum, and are 
there merely two cylindrical veins surrounded by a loose cellular sub- 
stance, and which have an anastomosis between them. In ascend- 
ing the spine they enlarge, but not continually, as they are some- 
what smaller in the cervical than in the dorsal vertebra. On the 
body of each vertebra they are rather larger than on the interverte- 
bral substance : this gives them a knotted appearance, which is es- 
pecially distinct in the loins. 

At the middle of each vertebra they are joined to one another by 
transverse branches, which pass beneath the posterior vertebral liga- 
ment, and receive the veins belonging to the cellular structure of 
the bone. Externally, they communicate with the vertebral veins 
in the transverse processes of the neck, with the intercostal, and 
with the lumbar veins, as an opening occurs between the adjacent 
vertebra. They also receive many delicate veins from the dura 
mater of the spine. These two trunks terminate at their upper end 
by an anastomosis, through the anterior condyloid foramen, with the 
internal jugular : they also terminate by anastomosis with the ante- 
rior occipital sinus and with the vertebral veins. 

From the arrangement of these sinuses, it appears that each bone 
of the spine has its own venous system or circle ; which also is the 
case in regard to the corresponding section of medulla spinalis in 
early life, when it occupies the whole length of the spine. Each 
of these circles, by the freedom of their anastomoses, therefore, forms 
a link in a long chain of venous circles belonging to the structure of 
the spine. 

* G. Breschet, Essai sur les Veines du rachis. Paris, 1819. Anat. Atlas, 
Figs. 483, 484, 485. 



VEINS OF THE UPPER EXTREMITIES. 291 



SECT. II. OF THE VEINS OF THE UPPER EXTREMITIES.* 

The veins of the upper extremities are superficial and deep-seated, 
and arise from the distribution of the arteries. 

The Deep-seated Veins are found in company with each arterial 
ramification, there being two veins to one artery generally. We 
thus have them observing the course of the arteries of the hand, of 
the fore-arm, of the arm, and of the shoulder. At the bend of the 
arm, the two radial and the two ulnar veins coalesce into the two 
brachial veins, which attend the brachial artery, one on each of its 
sides, and at intervals throw anastomotic branches across it. Some- 
times, but one of these trunks exists, with the exception of the 
lower part of the arm, where there are most commonly two. The 
trunk (or trunks, as the case may be,) is joined by the basilic 
vein, at a point varying from the middle of the arm to the axilla. 
These venae comites, or satellites, are invariably called after the 
arteries which they attend, and having no difference from the 
latter in relative situation, a farther description of them may be dis- 
pensed with. 

The Superficial Veins lie between the skin and the brachial apo- 
neurosis, and are considerably larger than the preceding. Their 
earliest roots are seen on the back of the fingers ; they then appear 
on the back of the hand, on the posterior of the lower end of each 
interosseous space. There are commonly six trunks in all : the one 
on the ulnar side of the hand and the three next to it, converge to- 
wards the middle of the back of the carpus into a single trunk ; the 
two others, one of which comes from the thumb and the other from 
the back of the fore-finger, converge to the outer end of the carpus, 
and there form a single trunk also. Between these several trunks, 
there are frequent anastomoses, and they, finally, assemble into two 
principal branches called the Cephalic and the Basilic Vein. 

The Cephalic Vein (Vena Cephalica, Radialis Cutanea) is the 
trunk which comes from the thumb and from the fore-finger, and 
has at first the name of Cephalica Pollicis. It ranges along the an- 
terior and radial margin of the fore-arm, and receives, continually, 

* Anat, Atlas, Figs. 486, 487, 488, 494. 



292 



CIRCULATORY SYSTEM 



an augmentation from small collateral branches on the back of the 
fore-arm. Having reached the bend of the arm, it then ascends along 
the external margin of the biceps flexor cubiti till it touches the lower 
margin of the pectoralis major muscle ; it then rises superficially along 
the interstice between this muscle and the deltoid, to within eight or 
ten lines of the clavicle, where it dips down to join the axillary 
vein. Along the arm, it receives some small secondary cutaneous 
branches. 

The Basilic Vein ( Vena Basilica, Cubitalis Cutanea) is larger than 
the cephalic, and begins by the trunk which comes from the ulnar 
side of the back of the hand, and is first called the Vena Salvatella. 
On the fore-arm, the basilic frequently consists in two long trunks, 
the anterior and the posterior ; in this case the posterior is the prin- 
cipal one, and runs along the internal posterior edge of the ulna, 
until it comes to the bend of the arm ; it then mounts over the latter, 
rising obliquely in front of the internal condyle. The anterior 
branch begins near the palm of the hand, runs up in front of the 
ulnar side of the fore-arm, and discharges itself into the median 
basilic vein over the brachial artery in front of the bend of the arm. 
These two trunks, or one as the case may be, receive the cutaneous 
veins belonoin£ to the ulnar side of the fore-arm. 

Above the elbow joint, the basilic gets below the fascia of the 
arm at the inner edge of the biceps, and about the middle of the 
arm becomes, by its junction with the venae satellites, the Brachial 
Vein; but sometimes, as mentioned, this junction occurs much 
higher up. 

The Median Vein '{Vena Mediana) arises, by branches, from the 
wrist, from the palm of the hand, and from the middle of the front 
of the fore-arm. It forms a trunk w T hich ascends in front of the 
fore-arm, and which a few inches below the bend of the arm, di- 
vides into two. One branch runs outwardly, in ascending for an 
inch or two, and joins at the outer side of the bend of the arm, the 
cephalic vein ; it is called, therefore, the Median Cephalic. The 
other branch continues to ascend, and, crossing obliquely the di- 
rection of the brachial artery, it receives, near the latter, the an- 
terior trunk of the basilic vein, and somewhat above the bend of 
the arm, runs into the proper basilic vein : it is called the Median 
Basilic. 



VEINS OF THE UPPER EXTREMITIES. 293 

There is frequently a departure from the preceding arrangement 
of the median vein ; the most common is where a trunk begins 
from the cephalic below the bend of the arm, and runs obliquely 
in front of the latter to join the main trunk of the basilic above the 
elbow joint. This oblique trunk stands in the place of median 
cephalic and median basilic, and receives successively the median, 
the anterior and the posterior basilic. It is frequently the median 
itself, and has a short anastomosis, in such case, with the cephalic 
vein. 

The Superficial Veins anastomose frequently with each other, 
so that, when they are all fully injected, a plexus of veins is found 
immediately beneath the skin of the upper extremity from one end 
to the other. The Venae Satellites also anastomose frequently by 
branches which cross the artery to which they belong. At the 
bend of the arm, at the wrist, and in different places, there are 
also anastomoses between the deep-seated and the superficial 
veins. 

The Axillary Vein ( Vena Axillaris) results from the union of the 
basilic with the brachial vein. It is below and in front of the axil- 
lary artery, being included in the same sheath with it, and also in- 
volved with the axillary plexus of nerves. It retains its name from 
the lower margin of the arm-pit to the under surface of the clavicle, 
where, like the artery, it is then called subclavian. In this course 
it is joined near the points where the corresponding arteries are 
given off, by the Anterior and the Posterior Circumflex Vein ; by 
the Scapular ; and by the External Thoracics. 

The Subclavian Vein (Vena Subclavia) extends from the termina- 
tion of the axillary to the vena innominata, where the latter is con- 
stituted by the junction of the internal jugular with the subclavian. 
In its course it goes under the subclavian muscle, and is in front of 
the subclavian artery from the beginning, but near it : afterwards 
it is separated from the artery by the latter going between the an- 
terior and the middle scalenus muscle ; whereas the vein runs over 
the anterior end of the first rib, in front of the insertion of the 
scalenus anticus. 

The Subclavian Vein is joined by some branches coming from 
the shoulder and from the lower part of the neck ; and, at the 

Vol, II.— 26 



294 CIRCULATORY SYSTEM. 

outer margin of the origin of the sterno-mastoid muscle, it is aug- 
mented by the addition to it of the external jugular. It terminates 
at the internal margin of the scalenus anticus, as mentioned in the 
vena innominata. 



SECT. III. — VEINS OF THE LOWER EXTREMITIES.* 

The veins of the lower extremities, like those of the upper, are 
deep-seated and superficial. The former follow the course of the 
arteries, and are the venae satellites; there being, for the most part, 
two veins for every artery as far up as the ham, and also as re- 
gards the muscular branches of the thigh. These vense satellites 
adhere closely to the artery, and are separated from each other by 
the latter. They also have frequent anastomoses with each other 
across the artery. 

The Popliteal Vein (Vena Poplitea) is a single trunk formed by 
the union of the anterior tibial, the posterior tibial, and the peroneal 
vein. It begins on the posterior part of the head of the tibia, and 
extends upwards through the ham to the perforation in the adductor 
magnus muscle, which transmits the femoral artery. It is situated 
on the posterior face of the popliteal artery, to which it closely 
adheres ; and behind it is the popliteal nerve, the continuation of 
the great sciatic. 

The Femoral Vein [Vena Femoralis) is the continuation upwards 
of the popliteal: it at first is placed behind the artery, but in a short 
space it gets to its interior face, and continues to adhere to it, in 
that situation, up to Poupart's ligament, where it becomes the ex- 
ternal iliac vein. At the usual distance below the groin, where the 
arteria profunda is given off, the femoral vein receives the vena 
cruralis profunda, which is derived from the branches of this artery, 
and is rather more superficial than it; the two, however, adhere 
closely together. Just below Poupart's ligament the femoral vein 
receives several small branches of veins corresponding with the ex- 
ternal pudic arteries. 

* Anat. Atlas, Figs. 493 to 497, inclusive. 



VEINS OF THE LOWER EXTREMITIES. 295 

The Small Saphena (Vena Saphena Minor Externa) commences 
by several small branches near the external side of the top of the 
foot, and the external ankle ; a trunk is formed by them behind the 
latter, which ascends along the tendo-achillis and the posterior face 
of the gastrocnemius muscle, collecting several small veins from the 
back of the leg in its course. This vein is superficial in its whole 
length, being placed immediately beneath the skin. In the ham, it goes 
for a short distance along the internal face of the popliteal nerve, 
and then makes a dip through the adipose matter there to empty 
into the popliteal vein. 

It is said, by Portal, that the branches of this vein become very 
apparent in persons who suffer from podagra, and from enlarge- 
ment of the lymphatic glands in the ham. In such case, their 
distention has been relieved by the application of leeches along 
them. 

The Great Saphena ( Vena Saphena Magna, Interna) is also super- 
ficial, has its primitive roots coming from the internal upper part of 
the foot, and from the sole of the latter. These branches are as- 
sembled into a trunk which passes upwards in front of the internal 
ankle, then ascends along the internal face of the leg, in a line cor- 
responding with the posterior margin of the tibia. The great 
saphena continues its ascent over the internal condyle near its posterior 
part, and then mounts up the internal face of the thigh, in aline cor- 
responding nearly with the internal margin of the sartorius muscle. 
It finally terminates in the femoral vein, about twelve or eighteen 
lines below Poupart's ligament, an opening being left in the fascia 
femoris for this purpose. 

In the whole of this course the great saphena is situated between 
the skin and the fascia of the lower extremity ; it is, consequently, 
so superficial, that in persons of moderate corpulency it is very 
visible, and by slight pressure above, along with the erect position, 
it becomes so much swollen, that it is easily opened with the lancet 
where it passes over the internal ankle. It receives, in its ascent, 
small branches from the anterior and posterior part of the leg, from 
the corresponding surfaces of the thigh, and near its termination it 
gets a few of the external pudendal veins. 

When the great and the small saphena veins are successfully in- 
jected, their branches are seen to form a considerable number of 



296 



CIRCULATORY SYSTEM. 



anastomoses, which thereby produce a remarkable venous net- work, 
just beneath the skin of the whole inferior extremity. 



SECT. IV. — VEINS OF THE ABDOMEN.* 

The External Iliac Vein, (Vena lliaca Externa,) being the con- 
tinuation of the femoral vein, passes into the abdomen, under Pou- 
part's ligament, and in contact with the internal margin of the ex- 
ternal iliac artery. It there receives the epigastric, and the circum- 
flex iliac veins, corresponding with the arteries of the same name; 
it also receives a vein of some size, which enters by the abdominal 
canal in adhering to the spermatic chord, and which comes from the 
coats of the testicle. f It keeps then along the internal side of the 
artery, somewhat behind it, at the superior margin of the pelvis, and 
joins the hypogastric vein opposite to the sacro-iliac junction, and 
thereby forms the common iliac vein. 

The Hypogastric Vein ( Vena Hypogastrica, lliaca Interna,) comes 
from the inferior part of the pelvis in front of the sacro-iliac junction, 
and in company with the hypogastric artery. It arises by branches 
corresponding with the distribution of the latter to the viscera of the 
pelvis, and to its external parts ; these branches are so numerous at 
particular points, and have such frequent anastomoses, that they are 
formed into a Plexus. Thus, there is a hemorrhoidal plexus for the 
lower part of the rectum, a vesical for the bladder, a sacral for the 
sacrum, a pudendal for the parts of generation in the male, a vaginal 
for the vagina, and an uterine for the uterus of the female. 

The Plexus Hemorrhoidalis, besides being connected with the 
hypogastric, also anastomoses with the branches of the vena por- 
tarum. 

The Plexus Vesicalis is different in the two sexes. In man it 
commences at the extremity of the penis by several branches, which 
unite into two trunks of considerable size, the Vense Dorsales Penis.J 
The latter go along the upper face of the penis, near or at its middle, 

* Anat. Atlas, Figs. 489 to 492, inclusive. 
f H. Cloquet, Traite D'Anat. 

% They are frequently found to unite into a single trunk, called, in such case, 
the Vena Magna Ipsius Penis. 



VEINS OF THE ABDOMEN. 297 

to the symphysis of the pubes, continually receiving in this course 
small trunks from the integuments of the penis and from the scrotum. 
They then get into the pslvis between the root of the penis and the 
symphysis pubis, and continue horizontally backwards on the side 
of the prostate gland, of the vesiculse seminales, and of the lower 
fundus of the bladder. They receive many branches from these 
parts, which, with the frequency of the anastomoses about here con- 
stitute the vesical plexus. The latter, finally, discharges into the 
lower part of the hypogastric vein by two or more branches. 

In the female the vesical plexus begins on the dorsum of the cli- 
toris, by several branches coming from it and from the vulva ; they 
get into the pelvis under the symphysis pubis, and on the sides of 
the urethra and of the vagina, forming upon the lower part of the 
bladder, and on the side of the vagina, with the assistance of branches 
from these viscera, a remarkable plexus, which also empties into the 
internal iliac vein. 

The Plexus Sacralis consists in an order of veins, anastomosing 
freely with each other, and corresponding with the middle and the 
lateral sacral veins. They communicate with the inferior end of the 
vertebral sinuses through the anterior sacral foramina ; they also 
communicate with the hemorrhoidal and with the vesical veins. 
They terminate in the venous trunks, nearest the origin of the ar- 
teries from which they are derived. 

The Plexus Pudendalis is derived from the branches of the inter- 
nal pudic vein which go to the perineum, to the posterior part of 
the scrotum, and to the integuments of the under part of the penis. 
The trunk formed by the assembling of these several ramifications, 
follows the course of the internal pudic artery to which it belongs, 
and gets into the pelvis at the lower part of the sciatic foramen, 
where it contributes to the formation of the hypogastric vein. 

The Plexus Uterinus consists in a considerable number of veins, 
which are distributed upon the surface, and in the texture of the 
uterus ; they are also found in abundance in the broad ligaments, 
where they anastomose with the ovarial veins. 

The Plexus Vaginalis comes from the anterior parts of the organs 
of generation constituting the vulva, as the labia majora, minora, 
and so on. It also arises from the whole surface of the vagina, sur- 
rounds it completely, and anastomoses with the uterine veins. 

The Gluteal, the Obturator, and the Ilio-Lumbar Veins, also con- 

26* 



298 CIRCULATORY SYSTEM. 

tribute to the Hypogastric; their description conforms so nearly to 
that of the corresponding arteries, that it is unnecessary to detail it. 

The Primitive Iliac Vein, (Vena Iliaca Primitiva, Communis,) 
formed by the junction of the External and of the Internal Iliac, 
extends from the sacro-iliac symphysis to the lower margin of the 
fourth lumbar vertebra, where it jdins the corresponding trunk of 
the opposite side of the body, to form the commencement of the 
ascending vena cava. In this course the left one passes obliquely 
across the body of the fifth lumbar vertebra, and beneath the right 
primitive iliac artery. 

The Vena Cava Inferior is situated on the front of the spinal co- 
lumn, to its right side, and extends from the lower part of the fourth 
lumbar vertebra; or, in other words, from the junction of the primi- 
tive iliac veins to the under end of the right auricle of the heart, into 
which it empties. It is larger than the Descending Cava. 

In its ascent it inclines very gradually to the right side of the 
spine, so as to reach the opening in the tendinous centre of the dia- 
phragm, through which it passes just before it terminates in the 
auricle. It is bounded on the left side by the aorta ; and above the 
latter it is in front of the left crus of the diaphragm. Its lower ex- 
tremity is crossed in front by the root of the primitive iliac artery ; 
it is also crossed in its ascent by the duodenum and the pancreas. 
Its upper extremity is behind the liver, and frequently passes through 
the substance of this viscus. 

It receives the middle sacral, the lumbar, the spermatic, the 
emulgent, the capsular, the hepatic, and the phrenic veins. 

The Middle Sacral Vein (Vena Sacra Media) forms, as has been 
just mentioned in the account of the branches of the hypogastric 
vein, a part of the sacral plexus. Its trunk follows the course of 
the middle sacral artery on the front of the sacrum, and discharges 
into the commencement of the vena cava, in the fork formed by the 
junction of the primitive iliacs. 

The Lumbar Veins ( Vence Lwmbaks) correspond with the lumbar 
arteries, and are commonly four or five in number on each side. 
Their primitive roots anastomose with the epigastric, the last inter- 
costal, and the circumflex iliac veins ; the dorsal branches of them 



VEINS OF THE ABDOMEN. 299 

also anastomose with the vertebral sinuses, through the intervertebral 
foramina. Their trunks pass along with the arteries, between the 
bodies of the vertebrae and the psoas magnus muscle, or through the 
fasciculi of the latter : those on the left side pass behind the aorta, 
in order to reach the vena cava, and are, consequently, longer than 
such as are on the right. 

The Spermatic Veins (Vence Spermaticce.) The right one extends 
from the testicle to the ascending cava, just below the emulgent 
veins ; while the one on the left empties into the left emulgent vein. 
They are larger than the corresponding arteries, and present some 
peculiarities in the two sexes. 

In the male, the extremities of these veins begin in the testicle, 
and issue from it through the tunica albuginea ; some of them also 
arise from the epididymis. They anastomose with the superficial 
veins of the penis and of the scrotum, and disengaging themselves 
from the tunica vaginalis, at its back part, are assembled into four 
or five anastomosing trunks ; which envelop the vas deferens and 
the spermatic artery, and compose a principal part of the bulk of 
the chord. Having passed through the abdominal canal, they are 
reduced on each side to one trunk, which creeps along the sper- 
matic artery on the front of the psoas magnus muscle, and in com- 
pany with the ureter. Somewhat below the kidney, the spermatic 
vein is again resolved into a sort of plexus, having frequent addi- 
tions from the veins, in the adipose substance of the kidney, and 
some also from the branches of the vena portarum in the mesentery, 
and in the mesocolon. It then is reduced once more into a single 
trunk, which terminates as mentioned. The term Corpus Pampi- 
niforme (vine-like) is, by some anatomists, limited to the last plexus 
formed by each spermatic vein, but it is also frequently extended 
to both.* 

In the female, the spermatic vein is not so large as in the male ; 
it comes from the ovarium and from the side of the uterus, and is 
joined by some small branches from the round ligament of the 
uterus, and from the Fallopian tube. Passing, outw T ardly between 
the laminae of the broad ligament of the uterus, it crosses the ex- 
ternal iliac artery, and in the subsequent part of its course is dis- 
posed of as in the male. 

* H. Cloquet, Trait. D'Anat. 



300 



CIRCULATORY SYSTEM. 



The Emulgent Veins ( Vence Emulgentes, Renales) are commonly 
two in number, one on each side, and extend horizontally from the 
fissure of the kidneys to the ascending cava. They are of a con- 
siderable size, and owing to the position of the vena cava, the left 
is much longer than the right, and crosses in front of the aorta. 
They open on their respective sides of the cava opposite to each 
other. The branches of which the emulgent vein is composed, 
coming from the ramifications of the corresponding artery in the 
kidney, assemble into the single trunk near the fissure of the kidney ; 
this trunk is joined by some small veins from the adjacent adipose 
matter and from the capsular renales, and on the left side, as men- 
tioned, it is also joined by the spermatic vein. 

The Capsular Veins (Vence Capsulares) arise from the arteries 
spent upon the capsular renales ; and are two in number, one on 
each side. That on the right discharges into the vena cava, while 
the one on the left empties into the left emulgent most frequently. 

The Hepatic Veins (Vence Hepaticce) take their rise in the liver, 
and collect into three principal trunks, which converging towards 
the ascending cava, discharge themselves into it, where it adheres to 
the posterior margin of the liver, immediately below the diaphragm. 
Two of these trunks come from the right lobe, and one from the 
left, moreover, there are several small hepatic veins which dis- 
charge themselves into the cava, and come principally from the Lo- 
bulus Spigelii. 

The Inferior Phrenic Veins (Vence Phrenicce Inferiores) arise in 
the diaphragm, from the corresponding arteries. They are two in 
number, and discharge into the ascending cava just above the he- 
patic veins. 



SECT. V. — OF THE VENA PORTARUM. 

The Vena Portarum is derived from the viscera of the abdomen, 
and presents the singularity of a vein ramifying through a gland, the 
liver, before its blood is returned to the general circulation. The 
arteries from which it draws its supply of blood are the superior and 
the inferior mesenteric, and the cceliac with the exception of its he- 



VEINS OF THE ABDOMEN. 301 

patic branch. The viscera of the abdomen, which contribute to it 
are the spleen, the gall-bladder, the pancreas, the stomach, the 
small and the large intestines, the large and the small omentum. 

a. The Splenic Vein ( Vena Splenica) is formed by several branches, 
which coming out separately from the fissure of the spleen, unite after 
a short course into a single trunk. This trunk runs in company with 
the splenic artery below it, along the superior margin of the pan- 
creas, it is not quite so tortuous as the artery itself, and proceeding 
from left to right, is joined to the superior mesenteric vein in front 
of the vertebral column. 

In this course, the splenic receives the small veins,* ( Vena Breves,) 
corresponding with the vasa brevia of the great end of the stomach, 
and then, successively, several branches from the pancreas. It like- 
wise receives the gastric, or the superior coronary vein of the sto- 
mach, the right gastro-epiploic, and the left gastro-epiploic of the 
same viscus, all of which correspond with the arteries distributed to 
the latter. 

b. The Inferior Mesenteric Vein (Vena Meseraica Inferior) corres- 
ponds with the inferior mesenteric artery, and, consequently, derives 
its primitive branches from the rectum by the upper hemorrhoidal 
veins, which anastomose with the lower ; from the sigmoid flexure 
of the colon ; and from the left descending portion of the latter. 
The trunk formed by these branches, ascends behind the perito- 
neum, between the left ureter and the aorta ; and going up behind the 
pancreas, is discharged into the splenic vein an inch or two from its 
termination. But, like the veins belonging to the lesser curvature, 
and the right side of the stomach, it sometimes empties directly into 
the vena portarum, or into the upper end of the superior mesenteric. 

c. The Superior Mesenteric Vein {Vena Meseraica Superior) is the 
largest of the trunks which contribute to form the vena portarum. 
It is derived from, the ramifications of the superior mesenteric artery 
upon the small intestines, the ileo-colic valve, the right ascending 
and the transverse colon. Its branches constitute in the mesentery 
and the mesocolon a vascular intertexture, forming arches and 
meshes adhering to the corresponding ones of the arteries. In the 
transverse mesocolon, it, like the artery, anastomoses with the infe- 
rior mesenteric vein. Its trunk being formed by the union of these 

* M. Bauer discovered, in 1824, valves in these vessels, contrary to the 
general analogy of the system of the Vena Portarum. His observations have 
been confirmed by H. Cloquet. 



302 CIRCULATORY SYSTEM. 

several branches, ascends the mesentery, and goes in front of the 
duodenum, where the latter crosses the spine ; immediately after- 
wards it gets behind the pancreas, and near its right end is joined 
by the splenic vein. It here, also, receives small branches from the 
duodenum, from the pylorus, and from the gall-bladder. 

The trunk of the Vena Portarum being formed behind the pan- 
creas by the union of the superior mesenteric with the splenic vein, 
extends from this point to the transverse fissure of the liver, 
and is about four inches in length. It ascends obliquely from 
left to right, behind the second curvature of the duodenum, being 
bounded on the right side by the biliary ducts, and on the left by 
the hepatic artery where it is surrounded by a great many nervous 
filaments and lymphatic vessels, with all of which it is united by a 
common envelope of cellular substance, and of Peritoneum, called 
the capsule of Glisson. Having reached the transverse fissure of 
the liver, it divides into two branches, which are each at a right 
angle to it, but in line with one another : they constitute the Sinus 
Portarum, of which the right branch being spent upon the great lobe, 
and the left upon the small lobe of the liver, are ramified almost to in- 
finity through the structure of the latter. The terminating branches 
of the vena portarum empty into the venae hepaticae. 

Several cases are recorded in the annals of anatomy in which the 
vena portarum, instead of going into the liver, discharged imme- 
diately into the ascending cava.* In such instances the hepatic 
artery is much larger than usual. According to J. F. Meckel, not- 
withstanding they are anomalies, yet, as in most other cases of de- 
viation from the general type of the human family, a striking analogy- 
may be found between them and what occurs in some of the lower 
orders of animals. Here the analogy exists with the invertebrated 
animals. 

* Lieutaud, Hist. Anat. Med. Huber, Obs. Anat. p. 34. Abemethy, Ph. 
Tr. 1793, part. i. Lawrence, Med. Ch. Trans, vol. v. 



PECULIARITIES OF THE IXETUS. ' 303 



CHAPTER IV. 



Of the Peculiarities in the Circulatory System of the Foetus. 

Owing to the want of respiration in the fetus, its circulation is 
conducted in a manner very different from that of the adult. More- 
over, its parasitical life requires an alliance, through the organs of 
circulation, with the mother. Its peculiarities, therefore, may be 
studied under two heads : those which arise from the want of respi- 
ration, and those which are required for its nourishment. The pe- 
culiarities of the first order are situated in the thorax, and those of 
the second in the abdomen. 



SECT. I. — OF THE PECULIARITIES OF THE FffiTUS, ARISING 
FROM THE WANT OF RESPIRATION. 

The Heart, at a very short period after conception, so early as 
about the end of the first month, is sufficiently developed to be in 
a state of great activity. The first indication of its existence, and, 
indeed, of the life of the new animal, is a small tremulous point, 
called the Punctum Salic-ns, from its incessant motion. The mus- 
cular structure of it is soon evolved, and in a few weeks becomes 
very manifest. At the earliest visible period of the heart in the 
incubated egg, which affords a satisfactory analogy, it consists of 
two vesicles united by a canal, (Canalis Auricularis of Haller.) One 
of the vesicles is the right auricle ; the other is the left ventricle, and 
is probably the first to pulsate. The aorta is also visible, as well as 
the vena? cavse. The circulation, at this period, is very simple: the 
blood starting from the left ventricle, is propelled into the aorta ; it 
is collected from the ramifications of the last into the two venae 
cavae, and thereby brought to the right auricle; it is then propelled 
by the right auricle through the canalis auricularis into the left ven- 
tricle, whereby its round is completed, and it then starts again. 
This is the most simple kind of circulation, and is found, in fact, 
during the whole life of such animals as do not breathe by lungs ; 



304 



CIRCULATORY SYSTEM. 



for example, fish. As the gills in them take the place of lungs, a 
branch from the aorta, spent upon the gills, is sufficient for their 
purposes of respiration. 

The terms right auricle and left ventricle have been used, because 
the cavities alluded to perform the functions of the adult state ; but 
in the progress of the development of the heart, a partition begins 
to show itself which ultimately divides each of them into two distinct 
chambers, whereby we have a right auricle and a left one ; a left 
ventricle and a right one. And the canalis auricularis is reduced 
from a canal into a short orifice, called Ostium Venosum, commu- 
nicating from the auricles to the ventricles, and which is afterwards 
divided into two, one for either side of the heart. The partition be- 
tween the ventricles is completed about the end of the second 
month of gestation, at a period when the aorta, from having been 
simple originally, is converted into tw T o canals, one of which be- 
comes the pulmonary artery. The partition between the auricles 
is not completed till birth. In cases of monstrosity, it is interesting 
to see how much the heart, at the end of uterine life, has still pre- 
served this original type of simplicity. I have formerly dissected 
a double fcetus, where from the parasitical character of one', no effort 
had been made for the development of the lungs of the latter. The 
consequence of which was, the parasites heart consisted only of the 
right auricle and of the left ventricle, and the pulmonary artery had 
not been formed at all, there being but the single tube, the aorta, 
which led from the left ventricle, and had a sort of arrangement in 
its branches depending upon the tendency to form pulmonary arte- 
ries.* 

At birth, the auricular septum has advanced so far that the commu- 
nication between the two cavities is kept up only by a deficiency, 
called the Foramen Ovale. This foramen, marked by a depression 
on the right side, admits a small quill, when conducted obliquely 
through it, and is protected on the left side by a valve, the edge of 
which is upwards, and which when applied, is just large enough to 
cover the whole foramen. The moment that the blood ceases to 
pass through the foramen ovale, which occurs at the first act of in- 
spiration, the valve is applied, and the aperture grows up by the ad- 
hesion of its edge. The mechanism of this process is sufficiently 
simple. So long as the principal current of the blood was into the 

* For a detail of this case, See North American Medical and Surgical 
Journal, Philad., Oct., 1826. 



PECULIARITIES OF THE FCETUS. 305 

right auricle, the valve was pushed off from the side of the septum ; 
but as breathing establishes, through the lungs, pulmonary veins, 
and left auricle, a current of circulation equivalent, both in quantity 
and force, to that through the two venae cavse and right auricle, a 
perfect equilibrium between the auricles is established, and the 
valve retains its place against the septum. Notwithstanding the 
incessant action of the auricles, during all the subsequent periods 
of life, this equilibrium, in the force and time of their contraction, 
remains uniform : a circumstance proved, conclusively, by the health 
and strength of adults in whom the valve has never adhered to the 
day of their death ; an observation made by many anatomists, and 
of which I have witnessed several examples. In one of them I 
passed two fingers readily from one auricle into the other, owing to 
the unusual size of the aperture. 

The valve which closes the foramen ovale is, first of all, scarcely 
perceptible ; but as the foetus advances in age, the valve advances 
in size, and is indeed, large enough to close the foramen some 
weeks before birth. It is formed from the lining membrane of the 
two auricles, with an intermediate cellular substance. 

The Valve of Eustachius, which exists also in the adult heart, is 
placed at the anterior semi-circumference of the orifice of the ascend- 
ing vena cava in the right auricle, one of its ends adhering to the 
anterior margin of the foramen ovale. This valve, contrary to the 
one in the foramen ovale, is larger in proportion as the foetus is 
younger, and, when first observed, covers the whole orifice of the 
vena cava ascendens; its opening, however, is in the direction of 
the current of blood in the latter. It also is formed by a duplica- 
tive of the lining membrane of the auricle ; and, from its disposition, 
determines the blood of the ascending cava to flow through the 
foramen ovale into the left auricle, either wholly or in part, accord- 
inw to the period of gestation. Its obliquity also gives a direction 
to the blood of the descending cava, into the right ventricle from 
the rio-ht auricle. These uses of the Eustachian valve were pointed 
out by the celebrated Sabatier;* their value will be illustrated here- 
after. 

The ventricles of the Heart, at birth, have the same structure 
and internal arrangement as afterwards; they are remarkable, how- 

* Traite d'Anat. vol. ii. p. 266. 
Vol. II.— 27 



306 



CIRCULATORY SYSTEM. 



ever, for being of equal thickness, or nearly so, an observation of 
Mr. John Hunter.* This fact is connected with the circumstance 
of their both contributing to the aortic circulation till respiration 
begins, owing to the pulmonary artery entering, during fcetal life, 
by its largest branch, into the aorta. 

The Ductus Arteriosus constitutes this branch of the pulmonary 
artery, and is, in fact, the continuation of the trunk of the latter into 
the aorta, immediately behind the origin of the left subclavian 
artery. The right and the left pulmonary artery at this period, are 
but inconsiderable trunks, incapable by any means of carrying off 
all the blood of the right ventricle ; the greater part of it, therefore, 
is conveyed by the ductus arteriosus into the descending aorta. As 
the contraction of the ventricles, like that of the auricles, is synchro- 
nous, it is evident that the column of blood in the descending aorta, 
is acted upon by both ventricles at the same moment. 

The ductus arteriosus preserves the principle of a single circula- 
tion in the foetus, which was first of all manifested by the two ven- 
tricles, constituting but one cavity, and by the aorta and pulmonary 
artery being but one trunk. At the first act of inspiration the lungs, 
which were before solid, and the thorax, which was compressed, 
are greatly augmented in volume by the introduction of air. The 
dilatation of the thorax, besides introducing air through the trachea, 
causes an increased flow of blood through the right and left pulmo- 
nary arteries, in order to fill the vacuum in the lungs. The pulmo- 
nary arteries become in that way permanently dilated, and the cir- 
culation is finally drawn off entirely from the ductus arteriosus, 
though this takes several weeks or months before it is completely 
accomplished. The ductus arteriosus in this time is continually 
contracting, and is at length converted into a ligamentous chord, 
like other arteries, whose circulation has been arrested. 

These are the several peculiarities which distinguish the fcetal 
circulation, owing to the privation of respiration; and it is clear, 
that the collective result is that of a circulation quite as simple as 
if the heart consisted of but two cavities; while, at the same time, 
it keeps this organ in a state of preparation for carrying on two dis- 
tinct circulations, one pulmonary and the other aortic, from the 

* Animal Economy. 



PECULIARITIES OF THE FCETUS. 307 

moment that respiration begins: so that the whole mass of blood is, 
in subsequent life, brought successively under the influence of res- 
piration, by having to pass unavoidably through the lungs. 



SECT. II. — OF THE PECULIARITIES OF THE CIRCULATION OF 
THE FCETUS CONNECTED WITH ITS NOURISHMENT. 

The Umbilical Vein, one of the constituents of the umbilical 
chord, brings the blood from the placenta to the fetus. This vessel 
is from three to four lines in diameter, and enters at the navel; 
thence it goes along the free margin of the suspensory ligament of 
the liver, and traverses the anterior half of the umbilical fissure, to 
terminate in the left branch of the sinus of the vena portarum. In 
this course through the liver, the umbilical vein sends off to the 
right and the left lobe, several small branches. As the intestinal 
circulation of the foetus is too small to send much blood through 
the vena portarum, it would be sufficiently correct to consider the 
sinus vense portarum as the bifurcation of the umbilical vein : but, 
as this might introduce a confusion into the description, it will be 
better to retain the adult nomenclature. 

The Ductus Venosus is a vein which occupies the posterior half 
of the umbilical fissure, and is about a line and a half in diameter. 
It arises from the left branch of the sinus portarum, opposite to the 
place where the umbilical vein entered or terminated, and is con- 
sequently in the same line with the latter. Traversing the posterior 
part of the umbilical fissure, it terminates in the left vena hepatica, 
as this hepatic vein is about joining the ascending cava, just be- 
low the tendinous centre of the diaphragm. Through this route 
much of the blood of the umbilical vein is carried directly to the 
right auricle of the heart, and then passed through the foramen 
ovale into the left auricle by the mechanism of the Eustachian 
valve. 

From these considerations, it is evident that the umbilical vein 
really performs the office of a vein till it reaches the liver, but that there, 
much of its blood is spent through the portal circulation, upon the 
structure of this viscus ; and that what remains is carried through the 
ductus venosus to the heart. Like other veins, it is furnished with 



308 



CIRCULATORY SYSTEM. 



valves, of which there are two ; one at its termination in the sinus 
portarum, and the other at the cardiac extremity of the ductus veno- 
sus.* The establishment of respiration, by putting the circulation 
into other channels, likewise causes its obliteration and final conver- 
sion into a ligamentous chord. The valve, at the sinus portarum, 
prevents the blood from taking a retrograde course, and thereby keep- 
ing the umbilical vein open ; the valve of the ductus venosus has the 
same effect upon the duct to which it belongs, and is aided by the 
current of blood in the left branch of the sinus portarum, setting 
across the mouth of the ductus venosus instead of plunging into it 
from the umbilical vein, as in foetal life. 

It is worthy of remark, that the left branch of the sinus portarum 
is bounded, on its right extremity, by the end of the vena portarum, 
and receives, about its middle, the umbilical vein. In the space, 
then, between the umbilical vein and the portal, the circulation, 
from the predominance of umbilical blood in foetal life, is conducted 
from left to right, but afterwards from right to left, as the portal cir- 
culation is established and the other is arrested. 

The Umbilical Arteries discharge the important office of conduct- 
ing the effete blood of the foetus to the placenta. They are the con- 
tinuations of the internal iliacs, and are two in number, one on either 
side ; they conduct off so much of the blood of the primitive iliacs, 
as to leave the external iliacs of a very small size. During the early 
months of uterine life, they are rather, indeed, the continued trunks 
of the primitive iliacs ; the branches from the latter being then so 
little developed as to appear quite subordinate to the chief function, 
of carrying the blood out of the foetus, to the placenta. But as the 
inferior extremities and the buttocks grow, these subordinate branches 
are more and more evolved. 

At birth, the umbilical arteries, after dipping very superficially into 
the pelvis, rise up at the sides of the bladder and converge towards 
the navel. They emerge at the latter, cling together and traverse 
the umbilical chord by twisting spirally around the umbilical vein, 
like two small strings wound in this way upon a larger one. Their 
diameter is from a line to a line and a half. They anastomose as 
they join the placenta, but not previously. 

Like the circulation between arteries and veins in other parts of 
the body, the capillaries of the umbilical arteries terminate in those 

* Bichat, Anat. Descrip. vol. v. p. 419. 



PECULIARITIES OF THE FCETUS. 309 1 

of the umbilical vein in the placenta. From the observations ot 
Wrisberg, Osiander and the highly distinguished Professor Chapman 
of the University of Pennsylvania, it seems that there is no direct 
vascular communication between the mother and the foetus. 

This opinion is founded upon the leading facts, that the finest injec- 
tions do not pass from one to the other ; that fetuses, after the death of 
the mother from haemorrhage, still live and retain their usual quantity 
of blood; that if the fcetus be expelled entire with the placenta and 
membranes unhurt, the circulation still continues. One example of 
which was witnessed nine minutes by Wrisberg ;* another fifteen by 
Osiander ;f some from ten to twenty minutes by Professor Chap- 
man ;$ another for an hour by Professor Channing of Boston, and 
Dr. Selby of Tennessee, § where a bath of tepid water was used 
to resuscitate the fetus. Also, from the observations of Breschet, it 
seems that the globules of the blood of the fetus, when inspected 
by the microscope, are different in appearance from those of the 
mother. || 

Mascagni says that he has made several most minute injections 
of the pregnant uterus, so as to cover with small vessels its whole 
internal surface, and to return the injection by the uterine veins : and 
yet he has never succeeded in injecting, in that way, the secun- 
dines.H 

I have, myself, repeatedly tried by minute injection to pass arti- 
cles from the fetal into the maternal vessels, and the reverse, but al- 
ways without success ; in two instances, the experiment was upon 
human subjects, and, in the others, on the cow. In one of the lat- 
ter, I perceived that some of the injecting matter thrown into the 
fetal vessels had got into the uterine veins ; but as the observation 
was in opposition to all the others, and solitary, I have no disposi- 
tion to array it against them, at least, until farther and more decided 
experience. My second experiment on the human subject was 
made in April, 1833, under the following circumstances : A white 
female, aged 24, died at the Alms House, suddenly, and in the 
ninth month of pregnancy ; the foetus was still in utero, but the mem- 
branes were ruptured. In the presence of several of the physicians 
and students, and with the assistance of my young friend, Dr. God- 

* Meckel, Man. D'Anat. vol. iii. p. 163. f Id - 

£ Chapman's Med. and Phys. Journal, vol. i. p. 6. § Id. 

f| Am. Med. Jour. vol. i. p. 193. 
TJ" Prodromo, vol. i. p. 127. 

27* 



310 



CIRCULATORY SYSTEM. 



dard, to whose suggestions and manipulations I am indebted for the 
chemical compounds resorted to, I injected through the aorta one 
gallon of the saturated solution of Prussiate of potash, and followed 
it with an equal quantity of a saturated solution of sulphate of iron. 
The injection penetrated very minutely, as might be expected, and 
the precipitate of Prussian blue coloured deeply many parts of the 
skin. On dissecting the uterus, the uterine arteries were found well 
injected, but the injection did not reach the umbilical vein or 
arteries, as was proved both by simple inspection and by chemical 
tests. 

Having cut out the uterus and taken it to the University, the ex- 
periment was continued the next day in the presence of a large con- 
course of students and several physicians. The umbilical vessels 
were first of all injected with a saturated solution of bichromate of 
potash, and then with a saturated solution of sugar of lead. The 
result was a strong, yellow precipitate, the bichromate of lead. The 
injection passed reciprocally from the arteries into the vein, and 
from the vein into the arteries, conformably to the direction in 
which it was thrown for the time. The sinuses of the uterus were 
then injected with similar materials to those of the uterine arteries; 
to wit, a solution of Prussiate of potash, followed by one of sulphate 
of iron. 

The umbilical vessels were then all filled with liquid plaster of 
Paris coloured yellow: and the uterine sinuses with liquid plaster of 
Paris coloured blue, of which they readily received eighteen ounces. 
A short time having been allowed for the setting of the injection, I 
cut into the substance of the uterus and of the placenta. No yellow 
injection was found in the vessels of the uterus, nor was there any 
blue injection found in the umbilical vessels of the placenta ; there 
was, therefore a deficiency of evidence of direct vascular communi- 
cation between the foetus and the mother. The placenta was infil- 
trated with Prussiate of iron, and considerable quantities of blue 
plaster were found in the cavity of the uterus. 

In the progress of the injection with the Prussiate of iron, into the 
uterine sinuses, the membranes were raised from the uterus in vesi- 
cations. 

The parts, having been distended and put aside to dry, at the 
end of a fortnight they were examined again by incisions, and the 
same evidence of the want of direct vascular communication was 
renewed. But the placenta was found to be infiltrated according to 
certain rules seeming to depend on its organization. The blue 



PECULIARITIES OF THE FCETUS. 311 

colouring matter on the part of the uterus, and the yellow on the 
part of the fetus, determined in it two parts, one uterine and the 
other fetal, closely and alternately interlocked, like a dove-tailing : 
the uterine processes passed to within a short distance of the free 
surface of the placenta, while the fetal processes went almost to the 
base of the placenta. The confines of the two colours were defined 
well by this abrupt termination, the borders of these dove-tails. The 
appearance would, perhaps, be better designated by the terms uterine 
lobes, and fetal lobes, alternately penetrating, so as to constitute 
the whole mass of the placenta. No distinct vessel of a blue colour 
could, however, be seen in the uterine lobes ; but a few very spare 
yellow ones were visible. On raising up these uterine divisions,, 
the orifices of the uterine sinuses were seen at their base. 

The inference from this experiment is, that though there is no 
direct connexion of blood vessels between the mother and the 
fetus, yet there is a part of the placenta which seems to hold a 
special connexion with the uterine sinuses, and which may possibly, 
therefore, by interstitial circulation, establish a connexion with the 
fetus. The facts are at any rate presented as they occurred. 

The effete blood of the umbilical arteries becomes regenerated in 
the placenta, assumes a brighter hue, and is returned to the fetus by 
the umbilical vein. According to the theory of Sabatier concerning 
the use of the Eustachian valve,, if the latter did not exist, the fresh 
blood brought to the heart by the ductus venosus, instead of being 
diverted into the left auricle through the foramen ovale, would be 
received by the right auricle, and transmitted, either wholly or in a 
great degree, into the right ventricle. It would then be passed from 
the latter through the pulmonary artery and ductus arteriosus into the 
descending aorta, so that no part of the system, above the junction 
of the duct with the aorta, could, receive the benefit of it : this would 
leave the head and upper extremities unsupplied with fresh blood. 
Moreover, much of the latter would be fruitlessly introduced, for it 
would depart almost immediately through the umbilical arteries. 
But the Eustachian valve determining the flow of blood of the 
ascending cava into the left auricle, its passage into the left ventricle 
is a matter of course : thence it begins the aortic circulation fairly, so 
that every part of the system participates in its benefits. 

The celebrated Wistar* has also happily suggested, that without 

* System of Anat. vol. ii. p. 76, 3d edition. 



312 ABSORBENT SYSTEM. 

this arrangement, the blood of the coronary arteries of the heart itself? 
the purity of which is so essential to the vigour of circulation, would 
otherwise have been effete, and, consequently, unfit for its object of 
refreshing the heart. 

The umbilical arteries become the round ligaments of the blad- 
der, after the circulation through them has ceased, with the excep- 
tion of their pelvic extremities, which, subsequently constitute the 
trunks of the Internal Iliac Arteries. 



CHAPTER V. 

Histology of the Absorbent System. 

The Absorbent System is one of the most interesting of those 
which compose the human body, both on account of its very gene- 
ral diffusion, and of the office of interstitial absorption that it inces- 
santly carries on, thereby removing the effete parts of the body and 
making room for the deposite of new ones. It is also called the 
lymphatic system, owing to the transparent colour of the fluid which 
it conducts. 

With the exception of an imperfect observation of some of these 
vessels in the mesentery of a goat, by Herophilus and Erasistratus, 
during the reigns of the Ptolemies in Egypt, 280 years before Christ, 
what is known of them is entirely a modern acquisition in anatomy. 
In 1564, Eustachius discovered the thoracic duct of a horse, which, 
in the ignorance of its use, he called vena alba thoracis. This fact 
remained insulated and almost forgotten for seventy years. In 1622, 
Asellius discovered the absorbents of the mesentery, and in the dis- 
cussions consequent thereto, the original observation of Herophilus 
and Erasistratus was relieved from an oblivion of nineteen centuries, 
to be again brought to light and admired. Asellius seems to have 
understood that the absorbents of the mesentery collect the chyle 
from the intestines, but his knowledge ceased there, for he thought 



LYMPHATIC VESSELS. 313 

that they discharged into the vena portarum.* In 1634, Weslingius 
saw the thoracic duct again ; and in 1649, ascertained that the chy- 
liferous vessels of Asellius terminated in it. In 1650, Olaus Rud- 
beck, a young man pursuing his anatomical studies in Leyden, saw 
first the lymphatic vessels of the liver, and in a few months after- 
wards injected similar ones in the loins, in the thorax, in the groins, 
and in the arm-pits. Thomas Bartholine, a teacher of great reputa- 
tion in those days, in a dissertation, dated in 1652, claimed for him- 
self the priority of these observations, and from the obscurity of 
Rudbeck, enjoyed for some time the merit of them. In 1654, 
Rudbeck published and set forth his own pretensions with such 
force, that he finally triumphed over his antagonist, but not until 
the whole world of anatomy had been set in commotion ; one party 
being for the professor, and the other for the pupil, and many bloody 
strifes having arisen between the students of the respective sides. 
In 1653, Jolyff, a celebrated anatomist, of London, proclaimed his 
own rights to this warmly contested honour; but the period being 
rather late, his name is scarcely associated with the history of these 
feuds. Almost a century then passed before there were many im- 
portant additions to the knowledge of those times. After which 
great contributions were made by Dr. A. Monro, f Dr. W. Hunter,} 
He\vson,§ and Cruikshank,|| but chiefly by the celebrated Mascagni,1f 
who, having imagined finely pointed instruments of glass for exe- 
cuting his injections of these vessels, succeeded in demonstrating 
them in almost every part of the body, excepting the spinal marrow, 
the brain, the ball of the eye, and perhaps the placenta. In some of 
these parts, however, he says he has seen them, and he speaks con- 
fidently of their existence, without exception, every where, even in 
the enamel of the teeth.** 

The Lymphatic Vessels are small, pellucid, transparent, cylin- 

* It is somewhat remarkable, that the celebrated Harvey, who had himself 
so much to complain of, in the obstinacy with which his cotemporaries adhered 
to ancient errors, for thirty years resisted the discovery of Asellius, and died, 
finally protesting against it. 

f De Venis Lymphat. Valv. Berlin, 1757-70. 

£ Med. Comment. London, 1762-77. 

§ Experimental Inquiries, London, 1774-77. 

|| Anat. of the Lymphatics, London, 1774-90. 

<R" Vasor. Lymph. Corp. Hum. Historia et Ichnographia. Sienna. 1787. 

** Prodromo della Grande Anatomia, vol. i. p. 1. 



^ 14 ABSORBENT SYSTEM. 

drical tubes, generally of about a line or less in diameter, whose 
trunks have been traced to all the external and internal surfaces of 
the body, and to the depth of all the organs, with the exceptions 
stated. It is only lately, however, that their existence on the ex- 
ternal surface of the skin has been put beyond doubt, by the ob- 
servations and injections of M. Lauth.* Their origin is so attenu- 
ated, that anatomists have come to no satisfactory conclusion in 
regard to its manner. 

The visible origin of the absorbents is, in some parts, as in the 
intestinal canal and on the glans penis, according to Breschet, as a 
reticulated intertexture, the meshes of which are so close as to leave 
scarcely an interval between them. In the peritoneal coat of the 
liver this reticulation is so fine and close that the membrane appears 
to be composed wholly of them : their connexion, however, with 
the deeper absorbents is so free that they cannot be preserved in this 
state owing to the subsidence of the injection, especially if it be 
mercury. Professor Fohman, of Heidelberg, whose injections are 
said to be of a most superior kind, is of opinion that in many cases 
these vessels have a cellular origin, such at least is the appearance 
of those in the cornea and in the umbilical chord injected by him. 
Muller, however, doubts the accuracy of his conclusions in regard 
to the character of these cells, f Fohman is indeed of opinion that 
cellular substance consists merely of lymphatics. 

•The earlier cultivators of this branch of study, not knowing their 
absorbent properties, conceived them to be continuations of the arte- 
ries applied to the reconducting of the serous part of the blood to 
the heart ; and considered the opinion substantiated by the circum- 
stance of their being occasionally filled by fine injections thrown 
into the arteries. More improved views of their uses caused the 
abandonment of this theory, and the substitution of their absorbing 
powers ; in which case the minds of anatomists became divided be- 
tween the ampulla-like mouth, or wide patulous origin of Lieber- 
kuhn, and the small orifices of Hewson. 

It is, perhaps, not possible to solve the question in regard to the 
mode of origin of the lymphatics, at least, in most parts of the body. 
Meckel, about the middle of the last century, asserted their conti- 
nuity with the veins. Mr. Ribes has seen matter injected into the 
vena portarum find its way into the lymphatics of the liver. On 

* Essai sur les Vaisseaux Lymph. Strasburg, 1824. 
f Loc. cit. p. 283. 



LYMPHATIC VESSELS. 315 

this subject, M. Chaussier says,* that, ignorant of the manner in 
which the arteries, veins, nerves, and lymphatics, arrange them- 
selves collectively into a glandular structure, or, in other words, 
into a capillary system, we cannot avoid ignorance of the part acted 
by the lymphatics alone ; we only know that the minute lymphatics 
form a portion of the elements of each viscus and structure of the 
body, and that they only become visible in becoming larger trunks. 
The absorbents in proceeding from their origins, in general be- 
come larger and less numerous, and form frequent anastomoses 
with one another. The proportionate increase of magnitude from 
the successive junction of trunks is by no means equal to what oc- 
curs in the veins. The larger superficial absorbent trunks of the 
extremities have not so much disposition to run into one another, 
hence they retain a size almost uniform from one end of the limb to 
the other. When fully distended, the appearance of absorbents is 
not regularly cylindrical, but knotted, owing to the frequent valvular 
interruptions in their cavities. The absorbents from all parts of the 
body, are finally united into two tubes ; one on the left, and the 
other on the right side of the trunk of the body, and which dis- 
charge their contents into the venous system, each on its respective 
side, at the junction of the internal jugular and the subclavian vein. 
The trunk on the right side receives the lymphatics of the right side 
of the head and neck, of the right lung, and right superior extremity ; 
while the trunk on the left, called the thoracic duct, receives all the 
chyliferous vessels and the lymphatics of the remaining part of the 
body. It would appear, from the observations of the younger 
Lauth,f that there are also other terminations of the lymphatics in 
the veins ; to wit, such as in the yet capillary state end in the veins 
of the minute structure of organs, and such as empty into them in 
the interior of the lymphatic glands. Previously to Lauth, this senti- 
ment of communication with the veins was strongly advocated by 
several anatomists and physiologists, for the following reasons: 1. 
That the known roots of the lymphatic system have an area much 
superior to that of the trunks in which they terminate. 2. That 
substances introduced into certain lymphatics by absorption or in- 
jection, have been found in the contiguous veins. 3. That a liga- 
ture upon the thoracic duct produced death only after ten or fifteen 
days, and then the articles which had been absorbed by the intestines, 

* Diet, des Sciences Med. Art. Lymphatiques. 
f Loc. cit. 



316 



ABSORBENT SYSTEM. 



were found in the blood. 4. And that injections had proved this 
communication. 

Notwithstanding the well known fact of injections, under certain 
circumstances, passing from the arteries into the lymphatics, some 
anatomists of modern date have hesitated in admitting a direct 
communication. M. Meckel has, indeed, rejected the notion en- 
tirely, on the ground that the fluid contained in the trunks of the 
absorbents is always the same as one finds at their commencement. 
For example, the lymphatics coming from the liver contain a fluid 
like bile; those which come from the mammse contain a fluid like 
milk; those which come from parts suffering from an extravasation 
of blood contain a sanguineous fluid ; the bronchial glands are 
coloured by the black pigment brought to them from the lungs ; 
poisonous matter, as that of the small-pox or venereal, irritates and 
inflames the lymphatics that lie in the course of its introduction into 
the system. For these reasons it would appear to him, that the 
arteries do not continue themselves into the lymphatics as they do 
into the veins. The observations of M. Lauth seem to have proved 
the point, that some of the lymphatics take their origin from the in- 
ternal surface of the arteries; and it may be through them that in- 
jections have been forced from one system into the other. In the 
case of the liver of a child, I have injected its absorbents very 
successfully from the arteries. 

The coats of the lymphatics generally are too thin and transparent 
for an investigation of their structure ; but as those of the thoracic 
duct are sufficiently thick for the purpose, one may estimate the 
structure of other trunks by it. It is thus ascertained that they 
consist of two coats, an internal and an external one.* 

The external coat is somewhat irregular on its surface, from its 
connexion with the adjacent cellular substance; and has a filamen- 
tous appearance more deeply, which has been considered as fibrous, 
or muscular, by some anatomists, owing to its contraction upon the 
application of certain stimulants. The internal membrane is ex- 
tremely fine and perfectly transparent, and is remarkable for its fre- 
quent duplications, whereby a system of valves is produced re- 
sembling those of the veins. These valves are generally of a 
semi-lunar or parabolic shape, and are arranged in pairs, though 
according to Lauth, f some of them are circular, and do not close 

* Valentin asserts that there is also a middle coat, and Henle that there is 
an internal epithelium. 
| Loc. cit. 



LYMPHATIC VESSELS. 317 

the canal entirely. The pairs are not placed at stated distances 
from one another, but vary in different parts of the body; in some 
places there are several in the course of an inch, and in others not 
one pair. As a general rule, they are less frequent as the trunk 
increases in magnitude; hence, the thoracic duct has but very few 
of them. The valves, by having their semi-circumference fixed, 
while the diameter is loose and inclined in the course of the circu- 
lation, prevent the retrograde movement of the contained fluid. An 
enlargement of the trunk at their outer face into sinuses, resembling 
those at the valves of the veins, gives also to the lymphatic trunk 
a knotted condition when it is fully injected. 

The coats of the lymphatic vessels, though very thin, are yet 
dense and extremely strong, much more in proportion than those of 
any other tubes. They are both extensible and elastic, possess 
striking powers of spontaneous contraction in the living body, and 
also contract in the dead, but to a less extent. They are furnished 
with arteries and veins, and probably with nerves also, from their sen- 
sibility in a state of inflammation. And, as they stand in need of 
a similar organization with other canals, their parietes are said also 
to have lymphatics. 

The absorbent vessels, are, by some, divided into lacteals and 
lymphatics,* the first term expressing those which convey the chyle 
from the intestines, and the second such as are found in other parts 
of the system. As the difference is more in the fluid conducted 
than in the structure of the vessels themselves, the division is rather 
superfluous. There is also a distinction of the lymphatics, as in 
the veins, arising from their situation ; some of them are called su- 
perficial, and the others deep-seated. The arrangement upon which 
this nomenclature depends, is found in the head, trunk, extremities, 
and in most of the viscera. The deep-seated trunks are the largest. 
They are the least numerous in the muscular parts of the body. 

* This division has been handed down from the time of Bartholine, who, 
not, suspecting the absorbing powers of the lymphatics, held them only as 
ortrans of circulation for restoring to the heart the serum of the blood. The 
sagacious mind of Dr. W. Hunter first imagined their absorbing powers, and 
established the theory of their identity of function, in this respect, with the 
lacteals. The priority of the theory was warmly contested for Dr. Monro, of 
Edinburgh. 
Vol. II.— 28 



318 



ABSORBENT SYSTEM. 



Of the Lymphatic Glands. 

The Lymphatic or Absorbent Glands or Ganglions, sometimes 
called waxen kernels in common language, are an appendage of a 
very important description to the absorbent system. They are flat- 
tened ovoidal bodies, of a reddish ash colour, indurated so as to af- 
ford a strong resistance to pressure, and of a variable volume, from 
a line to twelve lines in their long diameter. They are found prin- 
cipally in clusters or chains, and are more abundant in the neck, in 
the groin, in the arm-pit, in the mesentery, and about the bifurcation 
of the trachea. 

The lymphatic vessels, in their course towards the thoracic duct, 
have to pass through one or more of these glands. This rule is 
almost universal ; some exceptions, however, to it, in the case of the 
lower extremities, have been stated by Mr. Hewson, and in the 
case of the back, by Mr. Cruikshank :* the latter believes Mr. H. to 
have been under a misapprehension in this statement concerning the 
extremities, as it had not been verified by the result of his own in- 
vestigations. The vessels that enter into the glands are called vasa 
mferentia, while those that depart from them are the vasa efferentia. 
As, owing to the juxtaposition of many of these glands, the vessels 
between them are very short, this distinction would likewise seem 
almost superfluous, because there is scarcely space to apply the term 
efferentia, before the same vessels enter the consecutive gland, thereby 
becoming inferentia. For the most part, the vasa inferentia are 
more numerous and somewhat smaller than the efferentia. The 
former, as they enter the gland, radiate into smaller branches, while 
the latter are formed from the junction of smaller branches. 

Each lymphatic gland is surrounded by a capsule, resembling 
condensed cellular substance, which adheres very closely to the 
gland, and from which cause many anatomists are disposed to deny 
its existence, at least as a distinct membrane. They are also abun- 
dantly furnished with arterieg and with veins destitute of valves ; 
but though they are penetrated by nervous filaments, it is not yet 
satisfactorily ascertained that any remain with them ; it is, however^ 
more probable than otherwise. Their connexion with the surround- 

* Anat, of Absorb. Vessels, second edit. p. 79. London, 1790/ 



LYMPHATIC GLANDS. 319 

ing cellular substance is sufficiently loose to permit them, in certain 
parts, to be slid moderately backwards and forwards. When this 
motion is arrested, it is from inflammation about them. 

The capsule of the lymphatic gland, like that of other glands, 
sends processes within to keep its parts together, and to conduct the 
blood vessels. It also contains a peculiar fluid called, by Haller, 
succus proprius, which is principally found in young animals, di- 
minishes as they advance in age, and finally disappears. It is of 
various colours, but more frequently white ; it appears to have globu- 
lar particles in it, which the late Mr. Hewson, for divers reasons, 
thought to become afterwards the red globules of blood. 

When a lymphatic gland is injected with quicksilver, it appears 
to be made up by the minute branching of the vasa inferentia, and 
the roots of the vasa efferentia, the former being continued into the 
latter. There is also some appearance of small cells intermediate 
to these two orders of vessels. All anatomists admit the former 
opinion ; but many reject the latter, under a presumption that the 
appearance is delusive. The arguments seem to be in favour of 
their existence. Mr. Cruikshank,* whose address in these matters 
was certainly of the first order, declares that he never failed to per- 
ceive them, and particularly well, just as the mercury was entering 
the gland. This arrangement is still more readily made out in ani- 
mals, as the horse, ass, mule. It also seems, from his observations, 
that when there are more than one vas inferens and eflerens, there are 
cells for each set, which are kept distinct from the cells of the others, 
though they communicate freely with their cognates. Mr. Aber- 
nethy's investigations, on the mesenteric glands of whales, coincide 
with the views of Mr. Cruikshank : he states, indeed, the cells as 
being large spherical bags, into which the lacteals plainly open. 
The celebrated Mascagni also acknowledges, and, in fact, describes 
the cellular structure of these glands, f which he had ascertained 
both by quicksilver and by wax injections. The improved notions 
of modern anatomy, upon what is called the erectile tissue, that is, 
the cells intermediate to arteries and veins, as in the penis and 
other places, and now considered rather as the dilated extremities 
of vessels, would also assist in warranting the opinion advocated. 
The celebrated Ruysch thought that he had discovered acini in the 
lymphatic glands, and sent his injected preparations illustrative oi 

* Loc cit. p. 15, pi. iii. f Vasor. Lymph. Hist. 



320 ABSORBENT SYSTEM. 

them to Boerhaave. Some idea of the enthusiasm of the anatomists 
of old may be conceived by his saying "Quando jam clarius et per- 
fectius videbam hsec omnia, prse gaudio exsiliebam." 



When the absorbing powers of the lymphatics had been esta- 
blished by Dr. W. Hunter, they were for a long time considered as 
the exclusive functionaries in this operation ; and the opinions pre- 
viously entertained had sunk into such disrepute, from some expe- 
riments of Mr. John Hunter,* that they were considered rather as 
food for literary research and curiosity, than for deliberate adoption. 
In the year 1809, M. Magendie reported his experiments on absorp- 
tion, which seemed to favour the notion that the veins also assisted 
in this office, a theory as ancient as Galen. The more recent ob- 
servations of Fohman, in 1821, and Lauth, in 1824, on the com- 
munications of the lymphatics with the veins, in the midst of the 
tissues of organs, and in the lymphatic glands, seem now to explain 
away again the theories of the absorbing powers of the veins, and 
to reinstate the lymphatics in their reputed exclusive functions. It 
is also stated that an anatomist of Florence, M. Lippi, has still more 
lately found several large lymphatic trunks entering into the ascend- 
ing cava. The connexion of the lymphatic system with the vena 
cava ascendens, and also with the external iliac veins has been 
farther demonstrated by certain preparations, exhibited by M. 
Amussat to the Academie Royale.f M. Fodera has, however, 
again brought the subject under discussion, by multiplying the 
active agents of this function, and says, that his experiments prove 
that all organized tissues, enjoy it, and not certain parts only, as has 
been heretofore supposed ;| from which it results that most of the 
rules in regard to the application of local remedies are inexact, and 
that we should have more regard to the thickness and density of 
tissues, to. the quantity and rapidity of their circulation, than to 
simple locality. § 

* Med. Commentaries. 

f Am. Med. Jour. vol. i. p. 422. 

■^ Recherches Experimentales sur l'Absoiption et l'Exhalation. Paris, 
1-824. 

§ For a most interesting and instructive series of experiments on the laws 
and phenomena of absorption, see Philadelphia Journal of the Medical and 
Physical Sciences." Nos. 6 and 10. The experiments were executed by Drs. 
Lawrence, B. H. Coates, and Richard Harlan, of this city. 



ABSORBENTS OF THE HEAD AND NECK. 321 



CHAPTER VI. 
Of the Special Anatomy of the Absorbent System. 

SECT. I. — OF THE ABSORBENTS OF THE HEAD AND NECK. 

The Superficial Absorbents of the head are found in company 
with the several branches of the temporal, the occipital, the frontal, 
and the facial arteries, and, in order to get into the lymphatic trunks 
leading to the thoracic duct, follow or rather reverse the course of 
their respective arteries. There are at least two absorbent trunks 
for one arterial, and frequently more : those on the face are more 
abundant than such as are on the side of the cranium, owing to the 
excess of cellular substance on the former. The absorbents of these 
two regions anastomose freely beneath the external ear, between 
the skin and the parotid gland. 

The Deep-Seated Absorbents of the head have been followed to 
the membranes of the brain, but not farther. Ruysch observed 
them between the tunica arachnoidea and the pia mater, inflated 
with air, and called them vasa pseudo-lymphatica. Lancisius, 
Pacchioni, and others, assert their having found them in the pia 
mater. Doubts are cast upon these several observations, owing to 
such vessels not having been injected with quicksilver, and from 
the want of a valvular appearance in them ; also from the want of 
lymphatic glands in the cavity for the brain. Their existence, 
would seem to be sufficiently proved, both from general analogy, 
and from affections of the brain producing swellings in the glands 
of the neck. On the dura mater they have been traced along the 
course of its arteries. They descend from the interior of the cranium 
into the neck, along the carotid and vertebral arteries. The absence 
of lymphatic glands in the cranium may be accounted for from the 
fact, that the ready tendency of these organs to swell upon slight 
causes of irritation, would have rendered the individual liable to 
death, from compression of the brain, by their tumefaction. Mr. 
Cruikshank considers himself to have found lymphatic glands in the' 
carotid canal. 

as* 



325 



ABSORBENT SYSTEM. 



The Deep Lymphatics of the face, as those from the interior of 
the nose, of the orbit, of the tongue and mouth, attend the arteries 
which respectively supply those parts. 

These several absorbents, from the surface and from the interior 
of the head, descend to the base of the cranium, and then begin to 
pass through the chain of lymphatic glands situated along the course 
of the great blood vessels of the neck. They lie, for the most part, 
under the sterno- mastoid muscle, and, when successfully injected, 
are thought to form the most brilliant plexus of absorbents in the 
whole frame. On each side of the neck, one or more common 
trunks are, at length, formed; that on the left side joins the Left 
Thoracic Duct near its termination, while the one on the right assists 
in forming the duct peculiar to that side, the Right Thoracic Duct, 
or, more properly called, the right Brachio Cephalic. 

The lymphatic vessels of the muscles of the neck, and those of the 
thyroid gland, enter into the trunks of the neck. According to Mr. 
Cruikshank, those of the thyroid gland may be readily injected by 
plunging a lancet at random into its substance, andthen introducing 
ajr or quicksilver. 



Of the Absorbent Glands of the Head and Meek. 

The only claim of lymphatic glands to an existence in the cavity 
of the cranium, is founded upon the supposition that the Pineal, the 
Pituitary, and Pacchioni's Glands are of this character; but it is far 
from being established, and there seems indeed to be some doubt 
whether the glands found in the carotid canal, by Mr. Cruikshank, 
are not the carotid ganglion of the Sympathetic, noticed by Lau- 
monier. 

On the external surface of the cranium, over the insertion of the 
sterno-mastoid muscle, there are from four to six of a small volume; 
on the face there is one or more small ones, below the zygoma, and 
from two to four on the external surface of the parotid; there is one 
or more small ones situated in the substance of the parotid gland, 
which according to Burns, are generally the seat of tumours falsely 
attributed to the parotid itself. There are also some small glands 
along the facial artery as it ascends from the base of the jaw to the 
corner of the mouth. 

On the neck there are two or more small glands, immediately- 



ABSORBENTS OF THE HEAD AND NECK. 323 

under the skin of the symphysis of the jaw, and eight or nine around 
the submaxillary gland. The most numerous congeries of glands 
on the neck is, along its great blood vessels, and covered more or 
less by the sterno-mastoid muscle, being principally between its 
posterior margin and the anterior of the trapezius. Along the latter 
line there are about twenty, in addition to six just above the superior 
margin of the clavicle. On the trachea, just above the sternum, 
there are four, forming the upper end of a series which descends 
along the oesophagus and trachea to the root of the lungs. 



SECT. II. — OF THE ABSORBENTS OF THE UPPER EXTREMITIES 
AND OF THE CONTIGUOUS PARTS OF THE TRUNK OF THE 
BODY.* 

The superficial absorbents of. the upper extremities are very nu- 
merous, and lie between the skin and aponeurosis. They begin at 
the ends of the fingers and thumb; there being two or more branches 
for each, both before and behind. The posterior branches pass to 
the back of the hand and of the fore-arm: some of them, more espe- 
cially those from about the thumb, ran up along the radial side of 
the fore-arm. to the bend of the arm; but by far the greater part of 
them incline very gradually in a semi-spiral manner towards the 
ulna, and then to the front of the fore-arm. 

Such of the superficial vessels as come from the front of the fin- 
gers and hand, continue to ascend straight up the fore-arm to its 
bend. These vessels of the fore-arm are so numerous that for every 
few lines there is an ascending trunk on its circumference : some of 
them coalesce, others form plexuses, and. their number is much re- 
duced at the elbow. 

From the elbow the superficial lymphatics ascend to the axilla in 
fifteen or twenty parallel trunks, along the internal margin and the 
front surface of the biceps flexor cubiti. The outer side of the arm 
has comparatively but few absorbent trunks upon it, but some follow 
the course of the cephalic vein, penetrate with it into the axilla, and 
then join the inferior lymphatics of the neck. 

The Deep Absorbents of the upper extremity attend the arteries. 
* Anat. Atlas, Figs. 498, 499. 



324 



ABSORBENT SYSTEM. 



and are at least two for each principal artery. They anastomose 
with the superficial ones at intervals, and at last terminate in the 
axillary glands. As they follow strictly the course of the arteries, 
a farther specification is needless. 

The Superficial Absorbents of the contiguous portions of the trunk 
of the body are not by any means so numerous as those of the upper 
extremity ; they consequently are more distant from one another, 
and they also go along in a more serpentine manner. From the 
nape of the neck to the lower part of the loins they all converge to 
the arm-pit. The absorbents which are situated on the front of the 
pectoralis major muscle, and those on the side of the body from the 
arm-pit to the hip, also converge to the axilla. In regard to the 
two latter places, some of their absorbents, by penetrating the pa- 
rietes of the thorax or abdomen, respectively join the internal ab- 
sorbent trunk of these cavities. 

These several lymphatics from the upper extremity and from the 
trunk, traverse the axillary glands, and are successively reduced in 
number to four or five voluminous trunks, which surround the sub- 
clavian artery. While in the axilla they are re-enforced by the deep 
lymphatics from beneath the pectoralis major, the latissimus dorsi, 
and the shoulder. Their number being again reduced, they go along 
the subclavian vein over the first rib ; those of the left side open either 
into the thoracic duct at its termination, or into the subclavian vein, 
near it : but those on the right are finally assembled into the single 
large trunk, brachio-cephalic, which discharges into the angle of 
junction of the right internal jugular and subclavian vein. 



Absorbent Glands of the Upper Extremity. 

These glands are rarely found on the fore-arm, but when they do 
exist, it is in the course of the deep absorbents, and they are very 
small, and but few. From one to four are found scattered on the 
front of the elbow and internal condyle. From four to seven exist 
along the sheath of the brachial vessels and nerves. 

The axillary glands are very numerous, and of different sizes ; 
they are dispersed throughout the cellular substance of the axilla, 
reposing on the serratus major anticus, between the pectoral muscles 
and those of the shoulder, and being for the most part, below the 



ABSORBENTS OF THE INFERIOR EXTREMITIES. 325 

axillary vessels and nerves, but some reposing immediately upon 
them, and forming a chain from the lower part of the axilla to the 
clavicle. Their number is from fifteen to thirty-five or forty. All 
the absorbents which observe the route of the axilla to reach the 
thoracic duct have to pass through these glands. 



SECT. III. — ABSORBENTS OF THE INFERIOR EXTREMITIES, 
AND OF THE CONTIGUOUS PARTS OF THE TRUNK OF THE 
BODY.* 

The superficial absorbents, like those of the upper extremities, 
are placed between the skin and the aponeurosis, in the cellular 
tissue that contains the subcutaneous veins. They are also very 
abundant, and are found every few lines on the circumference of the 
limb ; they are, however, more numerous internally than externally, 
and, for the most part, run upwards. 

Those on the inner or anterior side of the limb are first perceived 
on the back of the toes and foot. They incline over the front of the 
ankle, and its internal face, to the inner side of the leg ; they then 
ascend over the inner side of the knee, and along the same side of 
the thigh to the groin. The superficial absorbents of the back of 
the lower extremity are first perceived on the sole of the foot. They 
ascend along the back of the outer ankle and of the leg above the 
knee ; they then incline semi-spirally inwards, so as to bring them- 
selves to the front of the thigh. These several absorbents, though 
there are but few on the foot, augment continually in number by 
new accessions in their ascent. All those on the posterior internal 
face of the thigh wind over its internal side, while such as are on its 
posterior external face wind over the outer side, to reach the in- 
guinal glands. 

The Deep Absorbents adhere to the arteries, being at least two 
to each, and adopting the same distribution and nomenclature. 
The anterior tibial set begins in the sole of the foot, and rises to its 
back between the first two metatarsal bones ; another branch begins 

* Anat. Atlas, Figs. 503 to 507, inclusive. 



326 ABSORBENT SYSTEM. 

on the dorsum of the foot. The first pursues the course of the an- 
terior tibial artery through the interosseal ligament to the ham, the 
second frequently joins the peroneal absorbents about half way up 
the leg. The posterior tibial and the peroneal absorbents, as they 
cruise along their respective arteries, do not require any farther com- 
ment. There is a fourth set of these deep absorbents, amounting to 
two or three in number, which attend the external saphena vein, and 
come from the external side of the foot. Getting between the heads 
of the gastrocnemii muscles, they are re-enforced by other trunks 
from this muscle ; some of the branches then associate themselves 
with the superficial lymphatics, and others penetrate the ham, so as 
to join the deep trunks there. 

The deep absorbents of the leg coalesce partially in the ham, and 
ascend along the popliteal artery. On the thigh, there are from four 
to eight of these trunks attending the femoral artery, and receiving 
additions as the latter detaches branches. 

There are two or three lymphatic vessels on each side of the 
penis, which begin at its glans and prepuce, and traversing the 
length of this organ, wind above the external abdominal ring to join 
the nearest inguinal gland. There are several from the side of the 
scrotum and perineum, which ascend along the chord and thigh to 
join also the nearest inguinal gland. In the female, those of the 
labia externa and clitoris correspond with those of the scrotum and 
penis. 

The superficial absorbent trunks, from the lower front of the ab- 
domen, are not numerous ; they descend and converge also to the 
inguinal glands. Some of those from the loins, such as do not as- 
cend to the axilla, advance to the inguinal glands. Those of the 
buttocks do the same. 



Absorbent Glands of the Lower Extremities. 

Absorbent Glands, below the knee, are not abundant, or indeed, 
very common ; yet, one or two exist sometimes in the course of the 
anterior tibial artery in the upper part of the leg. The popliteal 
glands are three or four ; they are small, and scattered at wide inter- 
vals in the fat of the ham around its vessels. From the latter to the 
groin, they are not usually found at all. 

The Inguinal Glands are amongst the largest in the system ; they 



DEEP ABSORBENTS OF THE PELVIS. 327 

repose along the anterior margin of Poupart's ligament and a little 
below, and are readily felt beneath the skin. The superficial vary- 
in number, in different individuals, from seven to twenty, being 
more numerous as they are smaller, and are placed between the la- 
minae of the fascia superficialis. They receive first of all, the super- 
ficial lymphatics of all the parts mentioned. The deep-seated are 
smaller, are a little lower down on the thigh, and lie along the course 
of the femoral artery, beneath the aponeurosis of the thigh ; they are 
from three to seven in number, but are much less constant than the 
superficial. 

SECT. IV. — DEEP ABSORBENTS OF THE PELVIS.* 

The Deep Absorbents of the parietes of the pelvis, as in other 
cases, attend the arteries of the part and have the same names. The 
obturators come from the heads of the adductor muscles, and pass- 
ing through the obturator foramen, end in the hypogastric glands. 
The ischiatics come from the small muscles on the back of the hip 
joint, and getting into the pelvis along with the ischiatic arterv, they 
also terminate in the hypogastric glands. The gluteals come from 
the three gluteal muscles, and entering the pelvis along with the 
artery at the superior margin of the sciatic notch, they likewise ter- 
minate in the hypogastric glands along with some vessels from the 
anus and the perineum. The ileo-lumbar, the sacral, and the cir- 
cumflex iliac absorbents, also follow their respective arteries and 
terminate in the nearest glands. 

The absorbents of the Testicle are numerous and large : accord- 
ing to Dr. W. Hunter,! they can sometimes be very completely 
injected by a pipe thrust into the substance of the testicle, and, 
according to Cruikshank,| very advantageously from the vas defe- 
rens, which has succeeded in my own hands. They form two 
layers, one superficial coming from the tunica vaginalis testis, and 
the other from the substance of the gland. They, finally unite, into 
some six or eight trunks, which§ ascend with the chord through the 
abdominal canal. Occasionally one or more of them is as large as 
a crow-quill. By following the course of the spermatic artery, they 
at last terminate in the lumbar glands. 

* Anat. Atlas, Fig. 500. f Loc. cit. 

% Loc. cit. p. 155. § Mascagni, loc. cit. 



328 ABSORBENT SYSTEM. 

The deep absorbents of the Penis accompany the arteries, and, 
therefore, either get into the pelvis beneath the symphysis of the 
pubes, or along the crura and the tuberosities of the ischia ; hence, 
a chancre on the prepuce causes bubo, while one on the glans very 
rarely does, and yet the constitution will be equally affected.* 
These absorbents terminate in the hypogastric glands. 

The deep absorbents of the Clitoris follow, in the same way, the 
internal pudic artery. 

The absorbents of the Urinary Bladder are also numerous, and 
pass in several trunks from its sides to the hypogastric glands. 
Those of the prostate gland and vesicular seminales are associated 
with them. 

The absorbents of the lower part of the vagina accompany the 
round ligament of the uterus through the abdominal canal, and, 
finally anastomose with those of the uterus. Those of the upper 
portion of the vagina are immediately associated with such as be- 
long to the uterus. 

The absorbents of the uterus are not so well seen in the unim- 
pregnated state, but in impregnation they are so prodigiously nume- 
rous that when injected with quicksilver, one is almost tempted to 
suppose that the uterus consists entirely of them. Mascagni's plate 
on this subject is an exquisite specimen. f As they all terminate in 
the hypogastric trunks, the latter are in such case as large as goose- 
quills 4 

The hypogastric plexus, from these several accessions from the 
parietes and viscera of the pelvis, becomes very large, and follows 
the course of the hypogastric artery in ascending into the loins. 

There are likewise some spermatic absorbents in the female, 
called so from attending the vessels of the same name. They come 
from the ovarium, the Fallopian tube, and the round ligament, to 
terminate in the lumbar glands : they anastomose below with those 
of the uterus. 



Of the Glands of the Pelvis. 

Some few glands lie beneath the gluteus magnus muscle, but 
the majority are within the pelvis. Those which are called the Ex- 
ternal Iliac are at least six, frequently more, and extend from Pou- 

* Cruikshank, loc. cit. f Loc. cit, £ Cruikshank, loc. cit. 



ABSORBENTS OF THE ORGANS OF DIGESTION. 329 

part's Ligament to the lower part of the loins, being planted along 
the external iliac artery, both above and below. The Hypogastric 
or Internal Iliac Glands are rather more numerous than the others, 
and form a chain along the hypogastric artery. They are much 
disposed to form large indurated masses from diseases of the rec- 
tum, uterus, and bladder.* 



SECT. V. — ABSORBENTS OF THE ORGANS OF DIGESTION-! 

The Absorbents of the Stomach are very numerous, and lie in 
two planes: one is superficial, being immediately beneath the peri- 
toneal coat, and the other is profound being placed between the 
muscular and the mucous coat. They are, finally, assembled into 
three divisions, which follow the course of the principal blood ves- 
sels of this organ. 

One division coming from the anterior and the posterior face of 
the stomach, converges to its lesser curvature, and passes through 
some six or eight small glands in the adjacent portion of the lesser 
omentum. Inclining to the right of the cardiac orifice, its trunks 
then pass through some glands common to them and to" the deep 
lymphatics of the liver. Their numbers being reduced, they then 
descend behind the pancreas, and terminate in the thoracic duct 
near the cceliac artery. 

The second division comes from the left inferior portion of the 
stomach, and from its greater extremity, and, blending with the ab- 
sorbents of the spleen and pancreas, goes with them into the tho- 
racic duct. 

The third division comes from the right inferior portion of the 
stomach, and, assembling towards the pylorus, is subsequently 
mixed with some of the absorbents of the liver and of the small in- 
testines, and goes along with them into the thoracic duct. 

The Absorbents of the Great Omentum join those of the stomach 
and of the colon, at the points most convenient to them. 

The Absorbents of the Small Intestines,, like those of the stomach, 
are both superficial and deep, and from the function of conveying 

* Cruikshank, loc. cit. f Atiat. Atlas, Figs. 501, 505. 

Vol. II.— 29 



330 ABSORBENT SYSTEM. 

chyle, have been called lacteals, or chyliferous vessels. As the 
chyle, however, can only be absorbed by the deep ones : as they 
and the superficial have common trunks, and as they also absorb, 
from the intestines, fluids not converted into chyle ; there seems to 
be no necessity for distinguishing them by a particular epithet. The 
deep are in the cellular coat of the intestine, and follow the ramifi- 
cations of the arteries, being double their number. The superficial, 
being immediately beneath the peritoneal coat, run for some distance, 
longitudinally, on the gut, and then turn off to the mesentery] at right 
angles. 

On the mesentery these absorbents are not rigidly bound to the 
course of the blood vessels ; they converge in a slightly tortuous 
manner from its circumference to its root. They anastomose with 
one another, by which their number is reduced ; and they also have 
to pass through the series of mesenteric glands. The lacteals of the 
duodenum and jejunum are larger and more numerous than those of 
the ileum, in the proportion of the greater extent of the internal sur- 
face of the former intestines, from the number of their valvulee con- 
niventes. The vessels of the mesentery, after having cleared the 
series of glands, and held some intercourse with the lymphatics of 
the spleen, liver, stomach, and pancreas, are reduced at last into 
one or more large trunks, which, observing the course of the su- 
perior mesenteric artery, empty near the root of the latter, but some- 
times lower down, into the thoracic duct. 

The absorbents of the Large Intestines are much less numerous 
than those of the small. They are also superficial and deep, and 
observe the course of the blood vessels. Those from the right por- 
tion and middle of the colon join the lacteals of the mesentery, 
while such as belong to the sigmoid flexure follow the inferior me- 
senteric artery up to the lumbar glands. Those of the rectum go 
partly into the lumbar and partly into the hypogastric glands, 
and as its blood vessels are more numerous than those of other 
portions of the large intestine, its absorbents are in the same propor- 
tion.* 

The Absorbents of the Liver are exceedingly numerous, and are 
* Cruikshank, loc. cit. 



ABSORBENTS OF THE ORGANS OF DIGESTION. 331 

also injected with unusual ease from the larger into the smaller 
trunks, from the imperfection of the valvular arrangements. They 
are also superficial and deep. 

The Superficial Absorbents of the upper surface of the liver run 
in several divisions, the number of which is unsettled. Those near 
the middle front of the liver assemble into six or more trunks, which 
ascend the suspensory ligament, and enter the thorax between the 
diaphragm and the sternum. They are joined by several trunks 
from the diaphragm, and continuing to ascend up the anterior me- 
diastinum between its laminae behind the sternum, they are re-en- 
forced by contributions from the pericardium, from the thymus gland, 
and from the anterior parietes of the thorax. The division then 
crosses the upper end of the descending cava, and those from the 
two sides assembling, they go in one or more large trunks along the 
left vena innominata, and finally empty into the left thoracic duct 
near its termination. Sometimes they enter into the right thoracic 
duct. It occasionally happens that a detachment of this division, 
instead of ascending through the mediastinum, is directed towards 
the coronary ligament of the liver ; and being there joined by 
other vessels, it enters immediately into the thoracic duct at the 
upper part of the abdominal cavity, or at the lower part of the 
thorax. 

Another division comes from the upper surface of the right lobe, 
and gaining the right lateral ligament, penetrates into the thorax 
through the diaphragm, and advancing along the costal margin of 
this muscle, terminates in the first division under the sternum. 
Sometimes one of its branches, thrice as large as a crow-quill, runs 
backward to the spine, and is inserted into the thoracic duct behind 
the oesophagus, without passing through any gland ; there are also, 
occasionally, several other arrangements of the trunks of this di- 
vision.* 

Another division comes from the upper surface of the left lobe of 
the liver ; and its trunks advancing to the left lateral ligament, get 
into the thorax through the diaphragm. Some of the trunks then 
run forward on the convexity of this muscle, to terminate in the 
trunks under the sternum, while others retire backward to end in 

* Cruikshank, loc. cit. 



332 ABSORBENT SYSTEM. 

the glands around the oesophagus, immediately above the dia- 
phragm. 

There are various departures from this general arrangement of the 
absorbents on the upper surface of the liver; as their trunks invari- 
ably reach the thoracic duct ultimately, the particular routes do not 
seem to be rigidly fixed. 

The Superficial Absorbents of thenmder surface of the liver pre- 
sent, also, diversities, but they are seldom arranged into so many 
divisions as those of the upper surface. They communicate freely 
with the latter, and also with the profound, and, finally, assembling 
in the transverse fissure, they descend along the capsule of Glisson 
to join and anastomose with the contiguous trunks from the alimen- 
tary canal, from the pancreas, and from /the spleen. 

The Deep Absorbents of the liver follow the branching of the vena 
portarum, and, emerging at the transverse fissure, pass through the 
glands in the capsule of Glisson, associating themselves at the same 
time with the superficial trunks, and having a common termination 
with them. By putting a ligature around the vena portarum of a 
living animal, many of them are included in it ; they then become 
exceedingly turgid, and are seen to diverge through the liver like 
the pori biliarii. 

The liver is said to be more abundantly furnished with absorbents 
than any other viscus. 

The Absorbents of the Spleen are also superficial and deep-seated. 
The former are between the peritoneal and the proper coat, and are 
injected with some difficulty in the human subject, but are very 
demonstrable and numerous in the calf. The latter emerge at the 
fissure of the spleen, and, traversing the glands that lie along the 
course of the splenic artery, receive successively the absorbents from 
the pancreas. They, finally, end in the thoracic duct, after recipro- 
cal junctions, and anastomose with the vessels from the stomach and 
liver. 

The Absorbents of the Pancreas are also numerous, and may 
be injected, contrary to their circulation, from those of the liver. 
They arise from the substance of the pancreas, like its vessels, 



ABSORBENTS OF THE ABDOMEN. 333 

by short trunks, which join those of the Splenic Plexus at right 
angles. 

The Absorbents of the Kidneys are superficial and deep ; the 
former, though numerous, are too small in the healthy state of these 
organs to be well seen, but they become very distinct from disease, 
and converge from its periphery to its fissure. The deep absorbents 
accompany the vessels, and, emerging with them at the fissure, are 
joined with the superficial; they all then run along the emulgent 
vessels, and have frequent anastomoses with those of the testicles or 
ovaries, and with those of the capsulae renales. These absorbents 
may be filled by putting a pipe into the excretory duct of the 
kidney. 

The Absorbents of the Capsular Renales unite to those from the 
kidneys, and, therefore, terminate with them in the lumbar glands. 



Of the Absorbent Glands of the Abdomen. 

The cavity of the abdomen contains many more glands that any 
other region of the body, on account of the very great extension of 
the serous system in it; of the functions exercised by its viscera; and 
of its being traversed by the absorbents of the lower extremities. 
Many of these Glands have already been described under the de- 
nomination of hypogastric, and external iliac ; in addition to which 
there are a few between the laminae of the meso-rectum in front of 
the sacrum. 

The Mesenteric Glands are exceedingly numerous, and amount 
to between one and two hundred ; they begin at an inch or two from 
the small intestines, and may be traced to the root of the mesentery. 
being placed between its layers, on the convex side of the upper 
mesenteric artery. As the intestinal canal is longer in some indivi- 
duals than in others, they are proportionately more numerous. Their 
largest size seldom exceeds that of an almond : those belonging to 
the jejunum are rather more developed than such as belong to the 
ilium, and they all augment in size as they approach the root of the 
mesentery. 

The Glands of the Mesocolon are placed between the lamina? of 

29* 



334 ABSORBENT SYSTEM. 

this membrane, near the intestine; they receive the absorbents from 
the large intestines, are much smaller than those of the mesentery, 
and their number seldom exceeds fifty. Some few of them are situ- 
ated near the root of the mesocolon. They are by no means so dis- 
posed to tumefaction from scrofulous affections as those of the Me- 
sentery. It is stated by Winslow, that he demonstrated to the 
Academy of Sciences at Paris, chyle in the absorbents of the Meso- 
colon ; this fact will assist us in accounting for the effects of nutritive 
clysters. 

The Gastro-Epiploic Glands are situated between the laminae of 
the omenta, where they join the curvatures of the stomach. Their 
number seldom exceeds four or five for each curvature, and they 
receive the absorbents of the stomach and omenta. 

The Cceliac Glands are those which belong to the liver, the spleen, 
and the pancreas ; they follow the course of the blood vessels of 
these organs, and are traversed by their absorbents. The trunk of 
the vena portarum is surrounded by them, and Mr. Cruikshank says, 
that he has seen the biliary and pancreatic ducts in a state of com- 
pression from their tumefaction. 

The Lumbar Glands are very numerous and large ; they are 
scattered over the whole region, from the base of the sacrum to the 
pillars of the diaphragm, lying on each side of the bodies of the 
lumbar vertebra?, and in front of the abdominal aorta and vena cava, 
being concealed by the root of the mesentery and of the mesocolon. 
They may be considered as continuations of all the preceding con- 
geries of glands in the abdomen, and, therefore, when they, along 
with the vessels leading to them, are successfully injected, they form 
so thick a plexus of absorbents, reaching from the pelvis to the con- 
cavity of the diaphragm, that the great blood vessels can scarcely 
be seen for them. Many of the vessels reaching from one to another 
are as large as a crow-quill. 



SECT. VI. — ABSORBENTS OF THE VISCERA OF THE THORAX. 

The Absorbents of the Lungs are thought to be next in abundance 
after those of the liver, and are likewise divided into two sets, the 



ABSORBENTS OF THE THORAX. 335 

superficial and the deep-seated. The former are beneath the pleura 
pulraonalis. Mr. Cruikshank* says, that they are not always to be 
found, though commonly he has readily shown them covering with 
their meshes the whole external surface of the lung. The larger 
meshes follow the interstices of the lobules, and within them are 
others of extreme delicacy. The same author states, that one of the 
easiest methods of finding them, is to inflate the lungs of a still-bom 
child, from the trachea, and the air in passing from its proper cells, 
will get into the absorbents ; a puncture being then made into one 
of the latter, quicksilver may be very readily introduced. Some of 
their trunks penetrate to the bottom of the fissures of the lungs, and 
pass through the glands there, while others continue more superficial 
along the internal face of the lung, and so reach the bronchial glands. 

The deep absorbents of the lungs observe the course of the pul- 
monary vessels and of the bronchia. They arise from the substance 
of the lung, anastomose very freely with the superficial vessels, and 
in parting from the lung, pass through the bronchial glands, where 
they are joined by the superficial. 

By the junction of the branches from the left lung, three consi- 
derable trunks are formed ; one, which is sometimes the size of a 
goose-quill, is inserted into the thoracic duct, immediately behind 
the bifurcation of the trachea ; another ascends between the trachea 
and the oesophagus, to join, the thoracic duct near its termination; 
and the third joins the glands belonging to the absorbents of the 
heart, f 

The absorbents of the right lung also coalesce into three principal 
trunks at the root of the lung: one of them ascends across the front 
of the superior cava, making, in its course, many elegant convolu- 
tions, and at length terminates in the second trunk on the left side4 
The other trunks, ascending on the side of the trachea, and having 
traversed their glands, discharge into the right thoracic or brachio- 
cephalic trunk, or else near it into the right internal jugular, or into 
the right subclavian vein. There are, in these respects, diversities 
in different subjects. 

The trunks of the Absorbents of the Heart follow the course of 
the coronary vessels, and distribute themselves by branches over its 
whole surface. They are, without previous management, easily 

* Loc. cit. p. 194. f Cruikshank, loc. cit. % Ibid - 



336 ABSORBENT SYSTEM. 

discovered ; but if the heart be macerated in water for several days, 
so as to become somewhat putrid, the absorbents are filled and dis- 
tended by the gaseous exhalation : on the puncture of one of these 
vessels and the introduction of a pipe, they may all be readily 
filled. 

There are three principal trunks of these absorbents ; one follows 
the right coronary artery to the root of the aorta, and then ascends 
over the front surface of the latter to the top of its arch, where it 
enters a gland. The other two trunks follow the two principal 
branches of the left coronary artery, and, coalescing near its origin, 
they ascend to the bifurcation of the pulmonary artery, and from that 
along the posterior face of the arch of the aorta, to enter a gland 
between it and the trachea. These several vessels subsequently- 
traverse the lymphatic glands about the trachea, common to the 
heart and to the lungs : and ultimately terminate under varied cir- 
cumstances, either directly or indirectly, in the left thoracic duct, 
the left internal jugular, or the left subclavian vein. Mr. Cruikshank 
says, that the right coronary trunk empties into the lymphatic trunks 
of the right side of the neck, which shows that there is no fixed 
arrangement. 

The Absorbents of the Pericardium may also be found ; they ter- 
minate like the others of the heart, in the bronchial glands, and are 
particularly associated with those of the thymus gland. 

The Absorbents of the (Esophagus are so numerous as to form a 
plexus from one end to the other of it. They run into the bronchial 
glands, and, therefore, have a common termination with the absor- 
bents of the heart and lungs. Mr. Cruikshank says, that he has 
reason to believe that he has seen life sustained through them alone 
and the absorbents of the mouth, in a case where stricture prevailed 
for some months just above the cardia, and where the food, after 
remaining for three or, five minutes in the oesophagus, was vo- 
mited up.* 

The Absorbents of the Thymus Gland are very abundant in the 
infant, but diminish with the rest of the structure in the adult : they 
terminate in the bronchial glands also. 

* A case somewhat similar occurred in the practice of Dr. Physick. 



ABSORBENTS OF THE PARIETES OF THE TRUNK. 337 



SECT. VII. — ABSORBENTS OF THE PARIETES OF THE 
TRUNK. 

In addition to the absorbents mentioned as belonging to the in- 
ternal and external parietes of the pelvis, there are some others 
belonging to this cavity, as the ilio lumbar, the sacral, and the cir- 
cumflex. 

The Iliq Lumbar Lymphatics come from the parts to which the 
artery of the same name is distributed, and, assembling into two or 
more large trunks which pass beneath the psoas magnus muscle, 
one of them joins the lumbar glands, and another the hypogastric. 

The Sacral Lymphatics arise from the cellular tissue in front of 
the sacrum and from the spinal canal in the latter. Emerging 
through its foramina in front, they terminate in the lower part of the 
lumbar and in the hypogastric plexus. 

The Circumflex Iliac Lymphatics attending the artery of the same 
name, arise from the lateral inferior parietes of the abdomen, in the 
thickness of its broad muscles ; the several branches assemble into a 
few trunks, which descend along the posterior margin of Poupart's 
ligament to terminate in the external iliac plexus. 

The Epigastric Absorbents are derived from the inferior anterior 
parietes of the abdomen, along the region of distribution of the epi- 
gastric artery. Their trunks coalesce into larger ones, and descend 
along this artery to end in the external iliac plexus, near the crural 
arch. 

The Lumbar Absorbents arise from the muscles of the loins, 
from the posterior part of those of the abdomen, and from the spinal 
cavity. Their trunks correspond with the Jumbar arteries, and 
passing beneath the psoas magnus muscle towards the spine, they 
terminate in the lumbar glands. 

The Intercostal Absorbents take their origin from the parietes of 
the thorax, and following the course of the respective intercostal 
arteries, pass through some small glands occasionally found be- 



338 



ABSORBENT SYSTEM. 



tween the external intercostal muscles near the heads of the ribs. 
The}' are there joined by trunks from the spinal cavity and from the 
muscles of the back, and afterwards passing through some small 
glands on the front of the vertebral column, they anastomose more 
or less with one another, and finally terminate in the left thoracic 
duct. The absorbents of the pleura costalis and of the posterior 
part of the pericardium terminate in the intercostals. 

The Internal Mammary Absorbents have their roots in the ante- 
rior region of the parietes of the abdomen, above the umbilicus, 
where they anastomose with the epigastric. They ascend, along 
with the internal mammary arteries, behind the sternal cartilages, 
pass through some small glands, and receive contributions from the 
anterior extremities of the intercostal spaces. Those of the left side, 
assembling into one or two trunks, cross in front of the left sub. 
clavian vein, traverse the inferior cervical glands, descend after- 
wards from this point, and terminate in the left thoracic duct, or in 
one of the contiguous trunks of the venous system. Those on 
the right execute the same movements, but terminate in the right 
thoracic duct, or in one of the contiguous venous trunks on that 
side. 

The Absorbents of the Diaphragm are exceedingly numerous, 
and very much connected with those of the liver. The anterior 
ones join the internal mammary absorbents, while the posterior fol- 
low the phrenic arteries, or go to contiguous trunks belonging to the 
intercostals. The front ones on the right side, then terminate in the 
right thoracic duct, while the remainder go in the various routes of 
the absorbents, with which they are connected, into the left thoracic 
duct. They are principally seen on its upper surface. Mr. Cruik- 
shank* says, that he once saw them to the amount of three hundred 
or more, filled with chyle from the mesentery that had passed 
through the substance of the liver. Asellius was, therefore, probably 
justified by an accident of this kind, in asserting that the lacteals 
went to the liver. 

The Absorbents of the Female Mammae, like their arteries and 
veins, are superficial and deep ; the former attend the external tho- 

* Loc. cit. p. 90. 



THORACIC ABSORBENTS. 339 

racic blood vessels, and the latter the internal mammary. The 
superficial arise from the circumference of the nipple, from the skin 
and cellular membrane, and according to the injections of Mr. Cruik- 
shank, communicate freely with the vesicles of the tubuli lactiferi. 
They run towards the axilla, having occasionally to pass through 
some glands which are situated half way ; they then enter the first 
series of glands of the axilla in their direction, and afterwards others 
successively, until they terminate in the lymphatic trunks of the up- 
per extremity, high up in the arm-pit. Some few of these superficial 
vessels ascend over the pectoralis major to the glands in the neck, 
just above the clavicle. 

The deep absorbents of the mammas arise from their thoracic face, 
and penetrating the intercostal spaces, join the absorbents that at- 
tend the internal mammary artery. 



Of the Absorbent Glands in the Thorax. 

There are, as mentioned, a few small glands in the intercostal 
spaces near the heads of the ribs between the internal and external 
intercostal muscles, intended to receive the lymphatics of these 
spaces. There are also several small ones situated on the front of 
the dorsal vertebrae, along the aorta and the oesophagus, in the pos- 
terior mediastinum. There are also from six to ten along the in- 
ternal mammary artery ; and some others in the anterior mediastinum, 
along the sternal face of the pericardium. They are said to be very 
rarely affected by disease. 

The most considerable and striking glands in the thorax are those 
called Bronchial or Pulmonary, which receive the absorbents of the 
lungs. They cluster about the bifurcation of the trachea, and follow 
the bronchia for some distance into the substance of the lungs. They 
are from ten to twenty in number, and vary in size from an inch to 
a few lines in diameter. Till puberty they have a reddish colour, 
but afterwards they become gray, and finally black, following in 
these respects the change of colour in the lungs. According to Mr. 
Pearson, their complexion depends upon the deposit of pure 
carbon. 

In pulmonary consumption these glands are always enlarged, and 
look scrofulous. 



340 ABSORBENT SYSTEM. 



SECT. VIII. — OF THE THORACIC DUCTS.* 

The Left Thoracic Duct (Ductus Thoracicus Sinister) is the main 
stream of the absorbent system to which almost all the others are 
but tributary, and by divers routes ultimately find their way into it. 
It begins about the second or third lumbar vertebra, in front of its 
body. Shortly after its commencement, while still in the abdomen, 
it suffers a dilatation more or less considerable, and varying in its 
shape in different subjects. This is called the Reservoir of Pecquet, 
or the Receptaculum Chyli ; the dilatation, however, is frequently 
absent, and does not seem to be an essential part of the structure : 
in our preparations at the University some have it, and others have 
it not. 

The thoracic duct enters the thorax between the crura of the dia- 
phragm, to the right of, and behind the aorta ; it then ascends on 
the front of the dorsal vertebras, between the aorta and the vena 
azygos, in front of the right intercostal arteries, and behind the 
oesophagus. At the fourth dorsal vertebra it begins to incline in its 
ascent to the left side, and then ascends into the neck near the head 
of the first rib ; it rises commonly as high up as the upper margin of 
the seventh cervical vertebra ; it then turns downwards and forwards, 
over the left subclavian artery within the scaleni muscles, and, finally 
discharges into the angle of junction of the left subclavian and in- 
ternal jugular vein. 

The preceding is the most simple, and perhaps the most common 
form, under which the thoracic duct is presented, but varieties are 
continually occurring in its place and mode of origin, in its trunk, 
and its manner and place of termination. It commonly begins by 
the union of three absorbent trunks ; one for each side of the pelvis, 
along with the corresponding lower extremity; and a middle one for 
the chyliferous vessels, which unites with the common trunk of the 
other two, a few lines above iis point of formation ; on other occa- 
sions, the chyliferous trunks join it in a confused manner by nine or 
ten distinct channels. Sometimes an intricate plexus of several 
large trunks; derived from the lumbar and mesenteric glands, by 
the gradual reduction of the number of meshes from the successive 
joining of trunks; begins to assume, at the crura of the diaphragm, 

* Anat. Atlas, Fig. 502. 



THORACIC DUCTS. 341 

the form of a solitary trunk, which is the thoracic duct. The trunk 
of the duct is also disposed to keep up the anastomosing plan, even 
in the thorax ; we hence see it sometimes dividing itself into two or 
three channels of equal size, which unite again after a shorter or 
longer distance, and perhaps in a little space repeat the same ar- 
rangement : sometimes a small arm is sent off, which runs along for 
an inch or two, and joins into the parent stream; sometimes spiral 
turns are adopted by the thoracic duct; sometimes nodosities, or 
small pouches are formed on its sides ; sometimes it is dilated at in- 
tervals in its whole circumference. Sometimes it splits into several 
channels at its termination ; one channel terminating in one vein and 
another in a contiguous one, of the several trunks forming the vena 
innominata ; on other occasions, instead of entering into a venous 
trunk of the left side, it goes into the corresponding one of the 
right. 

Commonly, it is about the size of a large crow-quill, but some- 
times as large as a goose-quill, or even still more voluminous, seem- 
ing to be in a varicose state, of which Mr. Cruikshank mentions an 
example where it was half an inch in diameter, and took two pounds 
of mercury to fill it. There is generally a pair of valves at the ter- 
mination of the thoracic duct, or if it be divided into several streams 
there is a pair at the embouchure of each, to keep the venous blood 
out of it. There are also valves in its length, but they are not 
numerous, and vary in different subjects. 

The thoracic duct, as stated, is the grand outlet for the lymphatics 
of the left side of the head and neck, of the left superior extremity, 
of the left side of the thorax, of all the intercostal spaces, of the 
viscera of the abdomen, and of the inferior extremities. Though 
those of the viscera of the abdomen and of the lower extremities 
have this route, yet, from the observations of Mr. Lippi, of Florence, 
as mentioned, they have also some more direct means of getting into 
the general circulation. For example, he has found several large 
lymphatic trunks emptying into the ascending cava, one of them 
opposite the third lumbar vertebra ; another into the primitive iliac 
vein : he has also found some of the lymphatics of the liver dis- 
charging into the vena portarum. 

The Right Thoracic Duct, (Ductus Thoracicus Dexter,) as it is 
called, but more properly the Right Brachio-cephalic, after the name 
given by M. Chaussier to the vein, is not more than an inch long, 
and descends to empty itself, as mentioned, into the junction of the 

Vol. II.— 30 



342 ABSORBENT SYSTEM. 

right internal jugular with the right subclavian vein. It is derived 
from the lymphatic trunks of the right side of the head and neck, of 
the right upper extremity, the superficial lymphatics of the right side 
of the thorax, the lymphatics of the right lung, of the right side of 
the diaphragm, and some of those of the right side of the liver, the 
courses of all of which have been detailed. 

Though the single trunk is formed from these several tributary 
streams, yet the latter have sometimes several embouchures into the 
venous system at or near the point mentioned, and, as on the other 
side of the body, there is a proper security, by valves from the in- 
troduction of blood into them. 

There is always an ample system of anastomosis, not only between 
the branches which concur to form the right and left thoracic ducts, 
but even between the ducts themselves,* so that if one be occluded 
or impeded, its circulation can be turned into the other, as in the 
case of veins. 

* Meckel, Man. D'Anat., torn, ii., p. 581. 



BOOK IX. 



PART I. 

HISTOLOGY OF THE NERVOUS SYSTEM. 

Nervous System. 

The Essential ingredient of this System is a peculiar animal matter 
called Neurine, the texture of which is so soft, that in the natural 
state it has the least possible consistence. It is, therefore, protected 
in a variety of ways ; by being enclosed in bone, where it is collected 
in large masses ; and by being surrounded by ligamentous or cellular 
matter, where flexure is required. 

The nervous system in man, and other vertebrated animals, con- 
sists in two portions of dissimilar forms ; one is spheroidal, elongated 
at its base into a cylindrical process, and is contained in the cranium 
and in the spinal canal ; the other is an assemblage of arborescent 
rays, which proceed from different points of the first portion, to 
every part of the body. The first portion is the Central or Internal 
part of the nervous system, composed of the Brain and Spinal 
Marrow ; while the radiating portion is called the External or Peri- 
pheral, and consists in the Nerves of the brain and spinal marrow. 

The nervous system is remarkable for its symmetry. As it is uni- 
versally double, it very seldom happens that any striking difference 
of it on the two sides of the body is manifested, particularly as re- 
gards its Central portion ; it is said, however, that aberrations, in 
this respect, are more common in man than in other mammiferous 
animals. 



344 



NERVOUS SYSTEM. 



The centra] portion of the nervous System is composed of two 
kinds of the substance called Neurine, distinguished by their colour 
and relative situation : one is improperly enough called Medullary, 
(Substantia Medullaris ,) but as the name is now sanctioned by uni- 
versal usage, it is impossible to dispense with it. The other is called 
Cineritious, (Substantia Cinerea) with, perhaps, sufficient propriety, 
from its colour. They are both of a soft pulpy consistence, and 
constitute the chief mass of the brain and spinal marrow : some an- 
atomists have desired to add, from a slight distinction of colour, 
two other substances, a yellow and a black, but that seems unne- 
cessary, and has not been generally acknowledged. These sub- 
stances differ from one another in regard to their quantity, the me- 
dullary being more abundant than the cineritious ; it is also harder, 
and receives fewer vessels. 

The cineritious, or gray substance of the brain and spinal chord 
is formed of globules, according to Valentin, of a spheroidal shape. 
These globules have a nucleus, and in the circumference of this a 
nucleolus. The quantity of these globules determines the shade of 
the gray substance, but there are parts of the latter of a darker colour 
which is owing to a pigment of the globule. 

It is thought by Muller, that the cineritious globules of the nervous 
system are connected together by peculiar filaments ; the same ar- 
rangement existing in the ganglia of nerves. 

The Medullary Matter, when quite fresh and scraped in particular 
directions has a filamentous condition, which may be rendered still 
more distinct by hardening it in alcohol, in boiling oil, in a solution 
of the neutral salts, or in diluted mineral acids. If an attempt be 
then made to tear it, it will be immediately perceived that the fibres 
separate in a fixed direction, and in no other. These fibres, are, in 
some instances, parallel ; in others, concentric j and in others, di- 
verging or converging.* 

The elementary form of white nervous matter consists in those fila- 
ments or threads, and which in the nerves are held together by cellular 
substance. Each filament in both the brain and the nerves consists 
in a membranous tube, containing a soft matter. In the brain the 

* See Lessons on Practical Anatomy, by W. E. Horner, for description of 
Brain according to Gall and Spurzheim. 



HISTOLOGY OF THE NERVOUS SYSTEM. 345 

latter is a mere pulp, but in the nerves it may be separated from its 
tube in a linear form for some distance. 

The fibres or filaments of the brain when pressed upon, become 
swollen at intervals so as to be knotted or like a string of beads, 
and if the pressure be much they are separated into globules of dif- 
ferent sizes. The elementary nervous fibres are smaller in the brain 
and spinal marrow than elsewhere ; in the nerves themselves they 
vary from 5 *<r to ih of an English line. 

The knotted appearance upon compression of the cerebral sub- 
stance and spinal marrow observed by Ehrenberg first, is also ascer- 
tained by him to belong to the nerves of special sensation, as the 
Olfactory, Optic, and Auditory. The sympathetic has also, to a 
limited degree, this feature. It was at first supposed to be from some 
peculiar attribute, but now is accounted for by the greater delicacy 
at points, of the investing membrane of the filaments. 

The two substances are variously placed in different parts of the 
nervous system : the surface of the cerebrum and of the cerebellum 
is formed by the cineritious matter, and the interior principally by 
medullary; while the surface of the pons, of the crura, and of the 
spinal marrow, is medullary, and their interior cineritous. Again, in 
other points, they are intermixed. The medullary matter is al- 
ways so arranged that it is never interrupted, but forms a con- 
tinuous whole ; while the cineritious is in detached masses, and is 
found where the central extremities of the nerves are implanted, 
or where there is an increase of medullary fibres. Some ana- 
tomists have even supposed that it existed at the peripheral ex- 
tremity of the nerves, and particularly in the rete mucosum of the 
skin. 

The fibrillse of the medullary tissue are united by a very fine and 
thin cellular substance, which may be seen by tearing them apart. 
This cellular substance is more condensed near the surface of the 
brain, where it is formed into a highly vascular membrane, the pia 
mater, and is continued along the nerves as a neurileme, or covering 
to them. 

All nervous fibres are exactly cylindrical though this shape is 
easily disturbed by the manner of examining them. When tested 
carefully, no doubt is left on this head, and especially if the fibre 
be taken, as suggested by Miiller, from the Valve of the Brain. The 
varicose or knotted condition may be evolved possibly by a species 

30* 



346 NERVOUS SYSTEM. 

of contractility being brought into play by the method of examina- 
tion, of which we have an example on a large scale in the Medulla 
Spinalis, which when taken from the spinal canal becomes corru- 
gated by a spontaneous contraction. 

Vauquelin's chemical analysis of the brain afforded the following 
results : 

Albumen ----- 7.00 

a v ,, ^ Stearin 4.53 ) f, oq 

Adipose matter < -p, • 70 C " " 

Phosphorus ----- 1.50 

Osmazome - - - - - 1.12 

Acids, Salts, and Sulphur - - - 5.15 

Water 80. 



100.00 



The Central Nervous system is abundantly supplied with blood 
vessels, but lymphatic trunks have not yet been injected in it. 

The Peripheral Portion of the Nervous System or the Nerves, 
are formed by parallel anastomosing fasciculi of fibres, perceptible 
to simple inspection, which may be reduced into fibrillae, and then 
again into filaments as small as the thread of a silk worm. The 
finest filament is enclosed in its appropriate sheath, so that the latter 
is a tube filled with nervous matter. The nervous matter is soluble 
in an alkali, and in that way may be removed ; the canals may then 
be filled with quicksilver or air, and their existence demonstrated. 
On the other hand, nitric or muriatic acid dissolves the sheath, 
but hardens the nervous matter, and renders it more distinct, so that 
the finest filaments are made obvious.* In either case it is evi- 
dent that the shape of the nerve is preserved. These filaments are 
supposed to be precisely the same with the fibres of the brain, 
excepting that their sheaths keep them more distinct from one 
another. 

The Primitive fibres of the nerves have close correspondence in 
all animals, being solely threads and never globular. 

* Reil, de Struct, Nerv. 



HISTOLOGY OF THE NERVOUS SYSTEM. 347 

The original observation on the tubular structure of the nerves 
and brain, is due to Fontana, since then it has been confirmed by 
numerous others, as Remak, Henle, Valentin, &c, so that it may 
now be considered as one of the well-ascertained points of anatomy. 

The cerebro-spinal nerves contain a small intermixture of gray 
fibres, derived, probably, from ganglionic globules. The sympa- 
thetic has in return, though principally formed of grayish fibres, 
some few white fibres. In the common nerves this modification 
by the presence of gray fibres is seen principally at the points of 
junction with the sympathetic. 

The sheath of the nerves, or the Neurileme (Neurilemma) forms 
a general envelope to the nervous fasciculi, as well as a particular 
one to each fibre, and is continuous at its central extremity, with 
the pia mater. Its divisions branch off and unite again at intervals, 
forming a species of reciprocal anastomosis, sufficiently represented 
by the plan of the large nervous plexuses, as they occur in various 
parts of the body. It is the general envelope which is obviously 
continuous with the pia mater, but the particular sheaths of the finer 
fibres are lost insensibly, so that these fibres appear naked in the 
centre of the nerve, at its central extremity, unless examined with 
a good glass. The same destitution of neurilematic covering is ob- 
servable at the peripheral extremities of the nerves, wherever the 
latter can be traced. The interior of these canals is traversed by 
processes which cross the nervous matter and sustain it. From the 
increase in size, the additional solidity, and the close adhesion of 
the nerves to the dura mater, where they pass out of their several 
foramina in the spine and cranium, there is no doubt that the dura 
mater contributes to the neurile me, though its structure is altered and 
made much less dense. The best evidence of this is the sheath of 
the optic nerve, and of the spinal nerves. This opinion, advanced 
by the ancients, has been strongly contested by Haller,* and by 
Zinn.f The tunica arachnoidea is too fine to admit of any positive 
opinion about the extent to which it follows the nerves. 

The neurileme has but little contractility, is solid and difficult to 
tear, and is supposed to be the secretory organ of the medullary 
substance. 

* Prim. Lin. f Meraoires de Berlin, 175&. 



348 



NERVOUS SYSTEM. 



The nervous fasciculi are, moreover, held together by cellular 
substance, which has in the progress of life, a tendency to the de- 
positing of fat. This cellular substance, in neuralgic affections, is sub- 
ject to infiltrations and redness, whereby it becomes hard. This 
circumstance has induced pathologists to consider the pain as de- 
pending upon its inflammation.* 

The optic nerve, owing to the size of its canals, furnishes the best 
example of structure, and the nerves of the muscles are next. There 
are, however, some peculiarities in different nerves ; as the obser- 
vations of Sir Everard Home have ascertained that the medullary 
filaments of the optic nerve augment in numbers and diminish in 
volume, from its origin towards its termination. The early light 
thrown upon these minute and interesting points of nervous organi- 
zation, has been derived from the researches of Reil and Fontana.f 

In addition to the preceding structure, the nerves present a satin- 
like undulated surface, with small bands that pass somewhat spirally 
and in a zigzag direction. The latter appearance is- illusory, and 
depends upon the contraction or shortening of the nerve when not 
stretched ; its seat is in the neurileme, and it accordingly disappears 
upon extension. 

Some years ago M. M. Prevost and Dumas asserted that they 
had found the ultimate filaments of nervesj as distributed to muscles, 
terminating in loops, either by anastomosis with other filaments or 
in a loop of the individual filament. The observations of Valentin 
and Emmert corroborate those of the preceding gentlemen. Va- 
lentin has found the same arrangement in the iris and in the ciliary 
ligament ; in the cochlea of birds ; in the sacs of the teeth ; and in 
the skin of the frog. This arrangement does not, however, exist as a 
universal one in the nerves of sensation, as in the retina of the verte- 
brated animals and of insects r§ in many of the nervous filaments of 
the labyrinth, which like those of the retina have a free extremity ; 
and also in the pituitary membrane, according to Treviranus. In 
the mesentery of the frog the nerves terminate in a net-work accord- 
ing to Schwann. 

* Beclard, Anat. Gen. p. 665. 

f Reil, de Structura Nervorum. Halae Saxonum, 1796. Henle, Remak, 
Valentin and several others, all of more modern date, have confirmed more or 
less the views of Reil and added to them. 

£ See Histology of Muscles. 

§ Miiller's Report on Nervous System. 



HISTOLOGY OF THE NERVOUS SYSTEM. 349 

The nerves abound in blood vessels; when a vascular trunk 
reaches them, one of its branches ascends and another descends, 
and, if successfully injected, the neurileme is covered by its capil- 
lary ramifications. As in the brain, the lymphatics have not yet 
been injected. 

There are three modes by which the nervous fasciculi unite with 
one another ; anastomosis, plexus, and ganglion. Anastomosis is 
the junction of the filaments, either of the same nerve or of different 
nerves, and the examples of it are very abundant. Plexus is an anas- 
tomosis on a larger scale, and occurs between the larger fasciculi of 
the same nerve, or of different nerves, whereby a very complete inter- 
texture of their fibres occurs. 

Kronenburg asserts that the primitive fibres of the cerebral nerves 
continue separate up to their ultimate distribution, and that, in their 
apparent union, they only change from one fasciculus to another, 
and that this arrangement prevails not only in the plexus, but in 
every part of the nervous trunk and its branches. This conclusion 
he founds upon his observations of the brachial plexus in mamma- 
lia, and of the lumbar plexus in the frog.* This opinion, first ad- 
vanced by Fontana, has now been so repeatedly proved by observa- 
tion up to the present time, that it is laid down as an axiom in ana- 
tomy that from whatever point a nervous fibre may arise, it runs to 
its termination as a thread without coalition with any other fibre. 
It hence happens that the innumerable points of origin for the nerves, 
have equally numerous points or places of termination, on the peri- 
pheral parts of the body. The accuracy of our sensations and of 
nervous intercommunication is supposed to depend essentially upon 
this distinction being observed ; otherwise the impressions would be 
of the most confused kind, and, as Muller observes, no local im- 
pression on a single definite point would be perceived by the 
brain, f 

The above rule, though now established for the white fibres of 
the brain and spinal marrow, is not so fixed for the gray fibres, 
as there is some doubt whether they may not be connected in the 
ganglia. 

Ganglions are knots which occur in the course of nerves, whereby 

* Muller's Report on Nervous System, p. 232, for the year 1836. 
f Page 651. 



350 



NERVOUS SYSTEM. 



Fig. 39 



they have, for the time, a great augmentation of volume. The gan- 
glions have a great variety of form and size ; they are parabolic, 
circular, crescentic and so on, and, in their general appearance, 
hardness, and colour, resemble somewhat lymphatic glands. When 
submitted to maceration, they are resolved into two kinds of sub- 
stance : one is filamentous and continuous with the nerves, adhering 
to the ganglion ; and the other is gelatinous in its consistence and 
of a reddish ash colour. The filaments, in penetrating the ganglions 
are deprived of their strong neurileme, which is continued into a 
sort of capsule that surrounds the ganglions. They pass uninter- 
ruptedly, through the ganglion, and, 
therefore, continue the several nervous 
chords into one another; but, in a 
complicated way. The elementary 
arrangement of the nervous ganglia 
consists in grayish matter of the same 
description with that in the brain ; and 
of nervous filaments in continuation 
with the nerves connected with the 
ganglion. The nerves are resolved 
into a very fine intertexture or plexus 
which forms its meshes around the 
globules of gray matter, and are then 
recomposed to pass out on the other 
side of the ganglion. The ganglions, like other parts of the nervous 
system, are very vascular. 




Globules of the gray matter 
of ganglia after Valentin. In 
one, a second nucleus is visible. 
The nucleus of several contains 
one or two nucleoli. 



The Ganglions are said to be simple and compound ; the first is 
where a single nerve produces the ganglion, and the second where 
the filaments of two or more nerves concur to form it. The simple 
ganglions are invariable in their form and situations, and belong to 
the spinal marrow, being formed upon the posterior fasciculi alone : 
this fact was first pointed out by Haase,* and has been subsequently 
confirmed by the observations of Scarpa and of Prochaska, and by 
the admission of anatomists generally. The exterior envelope is 
continuous with the dura mater, and the internal with the pia 
mater, from whence they have more firmness than other ganglions. 



* De Gangliis Nervorum. Lipsia, 1772* 



HISTOLOGY OF THE NERVOUS SYSTEM. 351 

The compound ganglions are found at divers stations about the 
body. 

The attention of the profession has been much directed latterly 
to the microscopical observations of Professor Ehrenberg, of Ber- 
lin, on the structure of the Nervous System.* The following is a 
summary of his doctrines on this subject. The instrument used 
being a microscope of Chevalier, of Paris, augmented in power by 
Pistor and Schiek, of Berlin. 

The organic structure of the Encephalon, the Spinal Cord, and 
the Nerves, presents : 

1. A set of straight tubes, like a string of mock pearl beads, and 
whose spheroidal enlargements are kept apart by an intermediate 
canal. These nodulated tubes he calls varicose, from their mecha- 
nical conformation or resemblance to varicose veins ; he also calls 
them jointed or articulated from their shape. These are parallel to 
one another, cross occasionally, are never seen to anastomose, and 
are like filaments : they contain a peculiar matter, designated the 
Nervous fluid, (Liquor Nervosus of Haller,) and are confined chiefly 
to the white or medullary portion of the Encephalon and Spinal 
Marrow. They are of a milky colour. 

2. A set of filamentous bodies, which are hollow or tubular, of a 
simple cylindrical shape, that is, not having the irregular surface or 
nodes of the preceding. They are uniform, and generally larger 
than the nodulated, though the latter are in places continued into 
the former. They contain a white viscid fluid, to which he gives 
the name of Medullary, and which is less transparent than the Ner- 
vous. These tubes are the one hundred and twenty-ninth of a line 
thick in the middle ; they are elementary, are not surrounded indi- 
vidually by a neurileme, are collected into fasciculi, which, in that 
state, have a neurileme, and these fasciculi are grouped into larger 
chords or nerves proper. The elementary tubes, though they pass 
from one fasciculus to another, do not discharge or empty into one 
another, their anastomosis being merely one of adhesion. These 
cylindrical tubes exist chiefly in the nerves. 

* Memoir of 1833-36 to the Academy of Sciences of Berlin, translated by 
David Craigie, M. D. Edin. Med. and Surg. Journ. Oct. 1837 : copied into 
Essays on Physiology, Phila. 1838. 



352 



NERVOUS SYSTEM. 



3. A granulated matter, some of the grains of which are very fine 
and some coarser, being disseminated through the others. 

This is confined to the cineritious substance of the convolutions of 
the cerebrum, to the laminated surface of the cerebellum, and to the 
cineritious part of the Spinal Marrow. 

4. The articulated tubes present patulous ends to this granulated 
collection, which ends are fitted for the purpose of receiving them 
directly, and for the distillation of the Nervous fluid, (Liquor Ner- 
vosus.) 

5. The cylindrical tubes of the motiferous nerves are immediate 
continuations of the nodulated tubes. This is perceptible in the 
nerves of the medulla spinalis and of the cerebrum, excepting the 
Olfactory, the Optic, and the Auditory Nerves, which are unchanged 
nodulated tubes. 

6. Professor Ehrenberg's observations on living nerves have not 
yet exhibited the circulation of a nervous fluid in them, but he de- 
clares neither for nor against it. 

7. The Ganglions, or Nervous knots, consist of the articulated 
tubes alone, or mixed with the cylindrical tubes. They have also 
a very fine net-work of blood vessels, with nervous granules inter- 
mixed with them. They are, in fact, comparable to brains. 

The Nervous System is the seat of intelligence, and also extends 
its physical influence to every part of the body. Both the one and 
the other qualities reside in its central portion: the first in the brain, 
and the second in the spinal marrow. When the communication 
between the brain and the spinal marrow is interrupted by an acci- 
dent, or in an experiment, the difference between the influence of 
the two is strongly marked:* the influence of the brain seeming to 
be entirely intellectual, so that an animal will even bear its removal 
without immediate death ; while the influence of the spinal marrow 
is so indispensable to life, that its destruction is followed by instan- 
taneous and perfect death. f Under common healthful circumstances, 
however, the two seem to exercise a mixed influence on all parts of 
the body; as, for example, upon the reception of distressing intelli- 
gence, the stomach ejects its contents, or refuses to receive more ; 

* Legallois on the Principle of Life. 

f Observ. and Exper. on the Nervous System, by W. E. Horner, M. D- 
See Chapman's Med. and Phys. Journal, vol. i. p. 285. 



INFLUENCE OF THE NERVOUS SYSTEM. 353 

alarming intelligence causes the heart to flutter and to palpitate, and 
both the bladder and the intestines to evacuate their contents. On 
the contrary, a proper degree of corporeal exertion strengthens the 
intellectual operations, while its excess debilitates them. That these 
several nervous influences are seated in the central part of the ner- 
vous system, seems proved by the fact ; that where there has been a 
congenital deficiency of all the limbs, or an accidental one, which, 
of course, removes a very considerable portion of the peripheral part 
of the nervous system ; animal life and the intellectual operations have 
still gone on vigorously. 

The following are some of the physical functions over which the 
nervous system seems to preside. 

Digestion ; the whole alimentary canal, from the mouth to the 
anus, is under its influence: first of all in mastication, then in swal- 
lowing, afterwards in digestion and the absorption of chyle, and 
finally, the passing of the effete matter out of the body. It has 
been sufficiently proved, by the experiments of several physiologists, 
that the section of the par vagum destroys the faculty of digestion. 

Respiration ; the mechanical act of this process, that by which the 
cavity of the thorax is enlarged so as to admit of the introduction of 
air, evidently depends upon the phrenic and the intercostal nerves. 
If the nerves which supply the structure of the lungs be alone inter- 
cepted, as the par vagum, either by ligature or section, the changes 
on the blood produced by respiration cease, and the animal dies. 

Secretion, exhalation, absorption, and animal heat, seem also to 
be dependent upon the integrity and the activity of nervous influence. 
The action of the heart, sensation and voluntary motion, are in the 
same predicament. 

The manner in which these several kinds of innervation is pro- 
duced, is unintelligible. One has supposed it to consist in a vibra- 
tion of the elementary fibres of the nerves ; another in an agitation 
of their elastic globules ; another in the transmission of an imponde- 
rable fluid, as ether, magnetism, electricity, and Galvanism. Reil 
has proposed, on this subject, what has been termed a chemico-vital 
hypothesis : according to him, the general action of parts depends 
upon their form and composition ; consequently, when the two latter 
vary, the first does also. M. Beclard* inclines to the opinion, that 
" the nervous system is the elaborator and conductor of an impon- 

* Anat. Gen. 
Vol. II.— 31 



354 NERVOUS SYSTEM. 

derable agent ; and, like electricity or magnetism, that by it we can 
explain all the phenomena of innervation: — The relation between 
the benumbing influence of electric fish and Galvanic phenomena 
on one part, and ordinary nervous action on the other ; — The prac- 
ticability of causing Galvanic phenomena by the nerves and muscles 
alone; — The possibility of producing muscular contraction, the chy- 
mifiant action of the stomach, the respiratory action of the lung, &c, 
in substituting a Galvanic for a nervous influence ; — The existence 
of a nervous atmosphere, acting at a distance around the nerves and 
muscles, and between the ends of divided nerves ; — The wrinkling 
of muscular fibres in contraction, and the relation of the finest trans- 
verse nervous fibres with those wrinkles : are phenomena of innerva- 
tion which nearly approach certain electro-magnetical ones." 

This subtile fluid, according to M. Beclard, seems to be formed 
every where, but principally in places where there is much vascu- 
larity along with the ash-coloured substance. It impregnates all the 
humours and organs. The blood seems to be especially endowed 
with it, and owes to it the properties which distinguish it during life. 
In consequence of which, life is essentially connected with the re- 
ciprocal action of the blood upon the nervous substance, and of the 
nervous substance upon the blood.* 

Sir Charles Bell, of London, has presented, in a very interesting 
light, certain functions of the nervous system :f by his researches it 
appears, that besides the nerves of vision, smell, and hearing, there 
are four other systems, having different functions, and extended 
through the whole frame. Those of Sensation ; of Voluntary Mo- 
tion ; of Respiratory Motion ; and nerves, which give unity to the 
body in harmonizing the functions of nutrition, growth, and decay, 
or whatever else is indispensable to animal existence.^ 

According to this theory, the several filaments of a nerve exercise 
one or the other function, but only the one ; these dissimilar filaments, 
being bound up in the same fasciculus, constitute a nerve or fascis, 

* M. Rolando (Saggio sulla vera struttura del cervello, e sopra le funzioni 
del sistema nervoso, 1809, Beclard, p. 622,) has been so much taken with the 
Galvanic manifestations of the nervous system, that in the laminated arrange- 
ment of the cerebellum, he has only seen a modification of the Voltaic pile. 

f Exposition of the Natural System of the Nerves of the Human Body. 
Philad., 1825. 

£ For a farther view of the present state of opinions on the physiology 
of the Nervous System, see Human Physiology by Robley Dunglison, M. D. 
Professor, &c, Miiller's Physiol, and Carpenter's Physiol. 



DEVELOPMENT OF THE NERVOUS SYSTEM. 355 

and they never exchange power with one another ; their anatomical 
differences, however, are such, as not to make obvious one kind of 
filaments from the others. Several columns of nervous matter form 
the spinal marrow r , six in all, three on each side ; the anterior for 
voluntary motion, the posterior for sensation, and the middle for 
respiration ; and it is probable that still more may be found out. 
The first and the third ascend into the brain, and the middle stops 
short in the medulla oblongata; hence, the function of respiration 
goes on so long as the medulla oblongata remains entire. These 
few principles, supported by several experiments, have enabled Mr. 
Bell to bring forward a system of no small importance, on the ana- 
tomy and physiology of the nervous system.* 

The development of the nervous system is amongst the earliest 
processes in the distinct evolution of the fcetal organs. f At the end 
of the first month, when the head is a mere swelling of one end of 
the small maggot-like being, the brain and the spinal marrow are 
not by any means distinct, but the parts being transparent, a limpid 
fluid holds their place. About the fifth or sixth week, the embryo 
having acquired a length of five or six lines, the rudiments of. the 
brain appear as vesicles containing a whitish and almost diaphanous 
fluid, while the spinal marrow represents a long canal containing the 
same, and communicating with the cerebral vesicles. 

In the early part of the third month, the brain and spinal marrow 
show very distinctly the rudiments of the several cavities, elevations, 
and fasciculi, which mark their subsequent mechanical arrangement 
of surface ; and from this period it is no longer difficult to trace the 
successive development of each part to the degree of perfection 
which it has at the time of birth. 

From the many observations made by Tiedemann on these points, 
he has deduced the conclusion, that the brain is produced by the 
superior part of the spinal marrow ; that is to say, by the medulla 
oblongata, which grows and is developed for the purpose. That 
this is proved, in the extension upwards and forwards of the two 

* The same subject was taken up, in an inaugural thesis, by a zealous and 
intelligent graduate of the University, now dead ; and, by a series of ingenious 
experiments, seems to have been generally proved and illustrated. Remarks 
on some of the Nervous Functions, by J. P. Hopkinson, M. D., in Chapman's 
Med. and Phys. Journal, 1823, vol. vi., p. 240. 

f Anat. du Cerveau, par. F. Tiedemann, traduit par Jourdan, Paris, 1823. 
Anat. Comp. du Cerveau, par. E. R. A. Serres, Paris, 1824. 



35G NERVOUS SYSTEM. 

principal fasciculi of the spinal marrow, and by a canal which is 
found in the spinal marrow of the foetus, being extended to the 
fourth, and even to the third ventricle ; also, by the cerebellum pro- 
ceeding evidently from the medulla spinalis, since its two crura may 
be traced growing from it, and subsequently uniting over the fourth 
ventricle, so as to form the especial structure of the cerebellum ; 
also, by the tubercula quadrigemina being derived from the corpora 
olivaria of the medulla oblongata, and by the thalami and the 
corpora striata proceeding from the corpora pyramidalia, and finally, 
forming the hemispheres of the cerebrum. 

In addition to the preceding proofs, comparative anatomy fur- 
nishes other illustrations. The brain becomes more and more com- 
plex as one ascends from fish to reptiles, from the latter to birds, 
and then to mammiferous animals. The spinal marrow is very 
voluminous in the inferior animals, while the brain only forms an 
appendix to it ; whereas if the spinal marrow were an appendix to 
the brain, we ought to find the last of a prior formation in foetuses ; 
and also in a perfect state in the lower animals, before a medulla 
spinalis could be observed.* 



The exploration of the anatomy of the Nervous System with the 
microscope having become a very favourite pursuit; for an expo- 
sition of the general results of such labours, see Progress of the 
Anatomy and Physiology of the Nervous System, during the year 
1836, by Professor Miiller, of Berlin. 

* Tiedemann, loc. cit. p. 157. 



BOOK IX. 



PART II. 

ON Till SPECIAL ANATOMY OF THE CENTRAL PORTION OP THE NERVOUS 

SYSTEM. 

CHAPTER I. 

Of tlic Spinal Marrow and Hs Membranes.' 

The Spinal Marrow, (Medulla Spinalis) though frequently de- 
scribed after the brain, as a continuation or appendage of it, ha? 
precedence, as seen, both in the period of its formation in the em- 
bryo, and in its importance to the functions of the animal system : 
it will, consequently, be proper to give it that priority in description 
to which its natural rank entitles it. 

It is placed within the vertebral cavity, and extends from the 
first vertebra of the neck to the first or second vertebra of the loins, 
inclusively. It is surrounded by three membranes, of which the 
Dura Mater is external, the Pia Mater internal, and the Tunica 
Arachnoidea between the other two. 



SECT. I. — MEMBRANES OF THE SPINAL MARROW 



Of the Dura Mater of the Medulla Spinalis. 

This membrane, forming the exterior envelope of the spinal 
marrow, extends from one end of the spinal canal to the other, being 

* Anat. Atlas, Figs. 509 to 520 inclusive. 
31* 



358 NERVOUS SYSTEM. 

continuous above with the dura mater of the brain, and terminating 
below in a cul-de-sac, or closed extremity, sending off branches 
corresponding with the several nerves. It does not adhere to 
the surface of the spinal canal, but lies loosely attached to it, 
with the exception of the first cervical vertebra, to which it is closely 
fastened. Between it, and the ligaments and periosteum on this 
surface of the bones of the spine, is a long, loose, and spare cellular 
substance, generally somewhat watery, and containing in the lum- 
bar and sacral regions, a reddish, adipose matter. 

This membrane is so much larger than the medulla spinalis, that 
it invests it very loosely and always presents a collapsed appearance. 
Where the nerves penetrate, it furnishes to each one, a sheath as far 
as the intervertebral foramen. Having reached the intervertebral 
foramen, the sheath then enlarges so as to enclose the ganglion, ad- 
heres by cellular substance to the contiguous periosteum, and is then 
insensibly lost in the tunics of the nervous trunk. Those sheaths 
are longer for the cauda equina than elsewhere, and, of course, 
observe the same successive obliquity with the nerves to which they 
belong. 

The internal surface of the dura mater is smooth and shining, 
which is owing to the tunica arachnoidea being reflected over it. 

This membrane has a fibrous texture, and with inconsiderable 
exceptions, is like that of the brain. 



Of the Tunica Arachnoidea of the Medulla Spinalis. 

This membrane is next to the dura mater, and is easily distin- 
guished by its extreme delicacy, thinness, and almost perfect trans- 
parency. It is destitute of red blood vessels. It forms a complete 
envelope for the medulla spinalis, and adheres to the Pia Mater 
very loosely by means of long, slender, and scattered filaments of 
cellular substance. If the dura mater be slit up its whole length be- 
fore and behind, and a blow-pipe be introduced at one end of the 
medulla, between the pia mater and the arachnoidea, inflation will 
cause the latter to rise ; and to present itself as a long capacious 
tube, detaching on each side processes which surround the roots of 
the nerves. These processes having reached the points where the 
nerves penetrate the dura mater, are then reflected upon its internal 
face, being spread over it, and thus give it the glistening appearance 



MEMBRANES OF THE SPINAL MARROW. 359 

The processes enclosing the fasciculi of the spinal nerves, are par- 
ticularly conspicuous about the Cauda Equina. 



Of the Pia Mater of the Medulla Spinalis. 

This third envelope of the spinal marrow forms also a complete 
investment of the latter, and adheres very closely to it. Its external 
face is smooth, and is in contact with the arachnoidea, from which 
it may be readily separated by inflating the latter. But from the 
middle of its internal face both anteriorly and posteriorly, a process 
or partition penetrates into the middle fissures of the medulla spinalis, 
and reaches to their bottom. From these partitions there proceeds 
a great number of small vascular canals, which pass in various di- 
rections through the medulla, and anastomose freely with each other. 
This arrangement is rendered sufficiently obvious by injecting the 
blood vessels, and then destroying the medulla in an alkaline solu- 
tion : or if the medulla be hardened by neutral salts or acids, it splits 
into many^longitudinal radiated laminse, divisible into cords, where- 
by the arrangement is made equally manifest. A fact of some con- 
sequence is thus established, to wit, the similitude between the 
structure of a nerve and of the medulla spinalis. 

At the inferior end of the medulla the pia mater becomes a single 
cord, which is continued among the cluster of nerves constituting 
the Cauda Equina to the lower end of the tube formed by the dura 
mater, and there it joins with the latter. As a membrane, the pir 
mater is much more complete than the corresponding one of the 
brain, has more strength, but is not so vascular. Its thickness in- 
creases in its descent. It is of a yellowish-white colour. It seems 
to hold the medulla somewhat in a state of compression, for when a 
puncture is made through it, the medullary substance protrudes like 
a hernia. It goes from the medulla to the fasciculi of nerves and 
forms their neurileme or sheath. 

The pia mater seems to impart great elasticity to the spinal mar- 
row, for when the latter is detached from the spine by the severance 
of its nerves; it contracts suddenly and forcibly, to the amount of 
from one to two inches. 



360 



NERVOUS SYSTEM. 



SECT. II. — OF THE SPINAL MARROW. 

Its general form is cylindrical, yet it has slightly the appearance 
of being flattened both behind and before. It departs also from the 
strict cylindrical shape, by being enlarged or swollen at particular 
points. One of these enlargements occurs in the neck, where the 
spinal canal is formed by the five lower cervical vertebra?, and the 
roots of the axillary plexus of nerves are given off. The enlarge- 
ment is in the transverse direction or axis of the spinal marrow, but 
not so much in its thickness, and terminates gradually both above 
and below. The medulla spinalis afterwards continues small, w T ith 
very slight undulations or nodosities, until within three or four inches 
of its lower extremity, when it again enlarges. The enlargement 
here, though sufficiently obvious, is not equal in actual magnitude to 
that in the neck, and is the place from which all the lumbar nerves 
and the three superior sacral proceed. It is then brought gradually 
to a point somewhat blunted, which most commonly does not descend 
below the first lumbar vertebra?.* The point is, in some rare cases, 
bifurcated, and by a transverse fissure above it converted into a 
tubercle. 

The spinal marrow, besides terminating so much above the lower 
end of the spinal canal, is much smaller in its diameter, even with 
the addition of its membranes, than the canal. This circumstance 
prevails, especially in the neck, and in the loins, where much motion 
is experienced; and, consequently, a provision is thus made against 
any injury to it from pressure. 

The Medulla Spinalis is marked off, longitudinally, into two sym- 
metrical parts, by one fissure in front and another behind, both of 
which extend its whole length, and are placed exactly in its middle. 
The contiguous edges or surfaces of each of these fissures adhere so, 
that it requires a slight maceration or dissection to render them evi- 
dent. The posterior fissure is decidedly deeper, especially at its 
upper part, than the anterior: but the latter, in return, is somewhat x 
broader. The difference in depth, however, is unimportant, as sub- 
jects are frequently met with in which it is not appreciable. 

* The Spinal Marrow at the third month of the embryo extends to the end* 
of the coccyx ; it then suddenly contracts to the second lumbar vertebra. The 
coccyx is cotemporaneously reduced from seven to four pieces. Serres. 



SPINAL MARROW. 361 

Moreover, on each side of the medulla spinalis there is a lateral 
fissure. It is not precisely in -the middle, but somewhat posterior, 
and penetrates inwards and forwards. In many instances it is 
merely a simple superficial depression, much less deep than either 
of the former. It does not run the whole length of the medulla 
spinalis, but terminates somewhere in the upper part of its thoracic 
portion by joining with its fellow after having converged regularly 
towards it.* The different opinions of anatomists on the existence 
of this fissure may be accounted for by its being readily found in 
early life, while it is obliterated or very indistinct in old age. This 
lateral fissure should be carefully distinguished from two others, one 
before and the other behind it, which extend the whole length of 
the medulla spinalis, and consist in a series of little depressions, 
running into each other and transmitting the filaments which form 
the roots of the spinal nerves. The posterior, of the last named 
lateral fissure, is deeper than the anterior, and penetrates in the 
same direction with the lateral fissure first mentioned ; it also, in 
like manner, joins its fellow, but only after having proceeded to 
within a few lines of the inferior end of the medulla spinalis. 

The substance of the spinal marrow being of two kinds, cineri- 
tious and medullary, the order of their position is reversed from 
what occurs in the brain ; for the cineritious is included or enveloped 
by the other. On making a transverse section, the cineritious will 
be found much less abundant than the other, and consisting of 
a thin transverse vertical lamina in or near the centre of the me- 
dulla: this part is joined at either end to a portion somewhat cres- 
centic, whose concavity is outwards, and the convexity inwards. 
The transverse part does not run into the middle of the crescent, but 
somewhat anterior to the middle, so that the anterior horn is shorter 
than the other, and is also thicker and obviously more obtuse. The 
cineritious or grayish substance is more abundant at the lower part 
of the medulla spinalis than it is above. In the foetus, at the end of 
gestation, it predominates below, occasionally, to the entire exclu- 
sion of the other. Rolando asserts that in the spinal cord there are 
two kinds of cineritious matter, the one commonly acknowledged 
and which he calls cinerea vasculosa ; the other at the posterior horn 
of the cineritious crescent, is said by him to be perfectly gray, and 
which he calls cinerea gelatinosa, being asserted to contain corpuscles 

* Meckel, Manuel D'Anatomie. 



362 NERVOUS SYSTEM. 

similar to the red particles of frog's blood. The medullary or white 
substance is more abundant laterally than elsewhere, and has its two 
symmetrical sides joined together by a thin lamina at the bottom of 
the anterior and the posterior fissure. 

Each half or symmetrical side of the medulla spinalis is itself 
divided into two cords, marked off from each other by the poste- 
rior horn of the cineritious crescent, and by the first described lateral 
fissure. Of these cords the anterior is, consequently, much the 
larger ; it is also longer and forms the inferior extremity or the point 
of the medulla spinalis. The posterior cord, though so much 
smaller and narrower than the anterior, is itself subdivided into two, 
by a slight but well marked split; of these last two cords, the one 
next to the posterior middle fissure of the medulla is smaller than 
the other. These arrangements according to Meckel, are much 
more obvious in the early life of the human subject, than afterwards ; 
and are particularly conspicuous in the brute creation. 

The thin white laminae by which the two sides of the spinal mar- 
row adhere to each other at the bottom of the middle fissures, are 
called, by modern anatomists, Anterior and Posterior Commissures. 
Their precise arrangement is not yet fully ascertained, but it is stated 
by Gall and Spurzheim,* that the Anterior Commissure is formed 
by transverse fibres or filaments, which adhere to one another from the 
opposite sides like a suture, or after a serrated fashion ; whereas, 
the Posterior Commissure is formed by a band of longitudinal fibres. 
There is also another Commissure, called Middle or Cortical, from 
its position, and from its being formed out of the transverse part of 
the grayish or cineritious substance. 

The cords which form each half of the medulla are differently 
disposed : the posterior continues on the side to which it specially 
belongs, while the anterior having got within the circumference of 
the first cervical vertebra, crosses over to the opposite side by de- 
cussating with its fellow. This decussation occupies the space of 
four or five lines, and interrupts, for that distance, the middle fissure 
in front of the medulla. It is not effected by the cords passing in 
mass from one side to the other, but each cord sends off four or 
five fasciculi, which are interwoven with their congeners, like the 
fingers of the two hands when interlocked obliquely. It is to be 
observed that the whole mass of the anterior cords is not subjected 

* Recherches sur la Syst. Nerv. et sur celu, du Cerveau. Paris, 1803. 



SPINAL MARROW. 363 

to such distribution ; for the fasciculi just described come from their 
anterior and from their posterior faces, while the intermediate part 
is permitted to pursue its course straight upwards. This decussa- 
tion, upon which so much interesting physiological speculation de- 
pends, has been known for the last century or more, and is spoken 
of by Mistichelli and Petit. There are other places where the fasci- 
culi of the spinal marrow seem to cross from one side to the other, 
but the fact is not yet verified sufficiently. 

The existence of canals in the spinal marrow has been from time 
to time announced ;* though authors differ much in the accounts of 
their position and extent. When such an appearance is presented, 
it is supposed, by some, to be either the result of disease or of acci- 
dent, with the exception of a small one of eight or nine lines long, 
which communicates at one end with the fourth ventricle, and is 
shut up at the other. f 

The central ends of the spinal nerves, according to Valentin, do 
not terminate with the spinal cord, but having joined it, ascend into 
the brain. The nerves below ascend directly upwards, but the 
higher ones pass inwards towards the centre of the cord almost to 
the gray substance, and are then directed upwards to the brain. In 
the white substance of the medulla spinalis, the nervous fibres are 
in coiftact, but upon the borders of the gray substance, they are in- 
termixed with its globules. Being subsequently dispersed in the 
brain, they form loops in the cortical substance and terminate in that 
way by mutual junction. | 

The spinal marrow of a child, is very easy to divide by tearing it 
into threads, running its w r hole length ; these threads do not seem 
to have any determinate number, but to be regulated by the healthy 
consistence of the spinal marrow, and the patience with which the 
process is pursued. If a spinal marrow has been macerated for 
some years in spirits, it may be broken or split up into radii, or 
segments, running from the centre to the circumference, like a tree, 
and these sections divided into thin, short, flat laminae adhering 
to, or anastomosing with such as are contiguous to them. Miiller 
found a similar arrangement in the spinal marrow of the Petromyzon 
Marinus, though he has never seen it in any other animal. 

* Gall, Portal, Morgagni, t Meckel, p. 605, vol. it. Bichat, vol. iii. p. 123. 

t Mailer, p. 655. 



364 



NERVOUS SYSTEM. 



The Spinal Marrow sends out from its sides thirty pairs of nerves, 
which, like the vertebrae, are arranged into cervical, dorsal or tho- 
racic, lumbar and sacral. Of these there are eight cervical, one of 
which, from its escaping between the occiput and the first vertebra, 
is most usually designated as sub-occipital ; and, therefore, the num- 
ber of the cervical nerves is reduced to the same with that of the 
vertebrae to wit, seven. There are twelve pairs of dorsal nerves, 
five of lumbar, and five of sacral. Occasionally, there is a sixth 
sacral nerve on each side, which augments the number of spinal 
nerves to thirty-one pairs. 

Every spinal nerve is formed from two roots on the same level, 
one before and the other behind, and each root consists in several 
fasciculi of nervous matter. The front root arises from the ante- 
rior cord of the medulla spinalis, and the other from the posterior 
cord. The posterior root is larger than the anterior, but has fewer 
fasciculi in its composition, and is not so filamentous. The two roots 
are kept asunder by the Ligamentum Denticulatum. The fasciculi 
of each are slightly connected by a loose delicate cellular substance, and 
as they are about penetrating the dura mater, each fasciculus collects 
into a single cord, which passes the dura mater through its appro- 
priate foramen. In this way the anterior and posterior roots are 
kept distinct till they have got to the outside of the membrane men- 
tioned ; but the foramina, through which they pass, border closely 
upon one another. The posterior root, then forms a ganglion of a 
round or oval shape ; from whose external extremity there proceeds 
a single nervous trunk, which is joined immediately at its com- 
mencement by the anterior root. 

With the exception of the ganglions of the sacrum, which are in 
the spinal cavity of that bone, these bodies are placed in the interverte- 
bral foramina. The size of the ganglion is generally proportionate 
to that of the nerve from which it proceeds, but not invariably so, 
as some of the sacral ganglions are in small excess over the size ol 
their nerves. 

The two nerves of the same pair, though generally symmetrical, 
or precisely resembling, are not constantly so ; sometimes one is placed 
higher than the other, and the number of the fasciculi may be greater or 
less. The roots of the nerves are much nearer, or cluster more 
at the extremities of the spinal marrow, than at its middle. 

The Cervical Pairs of Nerves are nearly horizontal in their course 



SPINAL MARROW. 365 

from the medulla spinalis to the foramina in the dura mater. The 
first one, or the sub-occipital, is strictly so; the others incline 
very gradually more and more downwards. They have, therefore, 
but a very short passage before they reach the intervertebral fora- 
mina. Their roots are so pyramidal, that the bases nearly touch each 
other, and, for the most part are connected by an anastomosing fila- 
ment, which goes from the upper margin of the nerve below, 
to the lower margin of the nerve above. These anastomoses con- 
necting the lower fasciculi with the upper, are both on the anterior 
and posterior cords of the medulla, but more uniformly as regards 
the latter. Modifications of this arrangement, which it is unneces- 
sary to specify, are met with in different subjects. 

The Dorsal, or Thoracic Pairs are much inferior in size to any 
other nerves, except the inferior sacral. Anastomosing filaments do 
not generally prevail, yet they are found occasionally, as in the neck, 
upon the two or three upper pairs. The first one has the broad py- 
ramidal or triangular root of a cervical nerve, and resembles it also in 
volume. The second is the smallest of any ; they then go on increasing 
in size to the lowest, but not in uniform gradation. They are suc- 
cessively more oblique, and consequently longer from their bases to 
their passage through the dura mater. 

The Lumbar and the Sacral Pairs arise closely upon each other, 
indeed in absolute contact successively, from the lower end of the 
medulla spinalis, and form a cluster of filaments resembling the tail 
of a horse, hence it is called Cauda Equina. As their place of 
origin is within the precincts of the first lumbar vertebra and the 
two or three last dorsal, they all observe a very descending course 
in their progress to the inter- vertebral foramina, and the lower ones are 
almost vertical. Notwithstanding they are in contact, and adhere 
by a loose cellular substance, yet there are no anastomosing fila- 
ments between the adjacent roots. From the sacral ganglions pre- 
senting the peculiarity of being situated in the spinal cavity of the 
sacrum, instead of in the foramina, the single nerve formed from the 
ganglion and the 'anterior fasciculus, has to proceed a distance 
more or less considerable in the spinal cavity before it can escape 
from it. 

Vol. II.— 32 



$66 NERVOUS SYSTEM. 



Of the Ligamenta Denticulata. 

These bodies are narrow semi-transparent bands and very thin, 
which are placed one on either side of the medulla spinalis, between 
the pia mater and the tunica arachnoidea. They commence at the 
occipital foramen, by an adhesion to the dura mater, and descend- 
ing between the anterior and the posterior fasciculi of the roots of 
the nerves, terminate somewhat above the inferior extremity of the 
medulla spinalis. 

Each one is, at its commencement, in front of the accessory 
nerve, and in descending is rather nearer to the posterior than to 
the anterior fasciculi. By its internal margin it adheres with a uni- 
formity somewhat interrupted by fissures to the pia mater, but the 
external margin has a very different arrangement ; for it sends off 
at intervals from twelve to twenty-four serrated or denticulated pro- 
cesses, which for the most part are placed between the fasciculi of 
cervical and of dorsal nerves. The extremities of these teeth are 
small, rounded and strong, are surrounded by the arachnoidea, and 
adhere very firmly to the dura mater, being pointed downwards. 
The position and connexions of each ligamentum denticulatum are 
such as to make it serve as a fastening; which use is additionally in- 
dicated by its fibrous texture, and by the necessity that the medulla 
spinalis has for such fastening, in consideration of its being so deficient 
in filling up the vertebral canal.* 

It is taught by many [anatomists, that the ligamenta denticulata, 
from the opposite sides, join at the lower end of the spinal marrow 
to form the single cylindrical cord, that passes thence to the lower 
end of the spinal cavity, and has been described as an emanation 
from the pia mater. I am, however, induced to think with Meckel 
and others, that general analogy is in favour of the latter. 



* An opinion has been advanced by Professor Pancoast that the pia roater of the 
elephant, of the bullock, and of man, forms by its duplicative the ligamentum den- 
ticulatum. The specimen of the former which I have aeen in his possession affords 
strong indications of that arrangement: at the same time, in examining its point of 
origin in man from the dura mater at the foramen magnum, its distinctly fascicu- 
lated and tendinous character there, is in opposition to this conclusion : the fissures 
which separate it along its internal margin from the pia mater are also not favour- 
able to this idea, which in other respects is plausible and ingenious. — Wistar's Anat> 
Vol. 2, p. 513. Phila., 1839. 



BLOOD VESSELS OF THE MEDULLA SPINALIS. 367 



SECT. III. — OF THE BLOOD VESSELS OF THE MEDULLA 
SPINALIS. 

The Arteries of the Spinal Marrow are derived from the Verte- 
bral, Intercostal, Lumbar, and Sacral Arteries. 

1. The posterior Spinal Artery {Arteria Spinalis Posterior) is the 
lowest branch of the vertebral, given off in the cavity of the cranium. 
It reaches soon after its origin, the posterior face of the Medulla 
.Spinalis, and runs to the lower extremity of the latter, on the side 
of its posterior fissure. Its course is parallel with its fellow and 
very serpentine. In its descent it is continually re-enforced by 
small branches which get into the spinal cavity through each of the 
intervertebral foramina, they being twigs from the Vertebral, Inter- 
costal, Lumbar and Sacral Arteries. 

2. The Anterior Spinal Artery [Arteria Spinalis Anterior) arises 
above the last from the vertebral. Shortly after its origin it unites 
with its fellow into a common trunk, which descends along the an- 
terior fissure of the medulla spinalis, but is subject to interruptions. 
It also is re-enforced by twigs from the same arteries that pass 
into the spinal cavity through the intervertebral foramina. In its 
whole course it sends ofF branches from each side to the medulla 
spinalis. 

The Cauda Equina is supplied by arteries from the Lumbar and 
from the Sacral Arteries which reach it through the foramina, be- 
tween the vertebrae and in the sacrum. 

The veins of the Spinal Marrow are very abundant. A large 
one on each side of the middle line, called the Sinus Columnar 
Vertebralis, is situated in the spinal cavity, on the posterior face 
of the bodies of the vertebras, between their ligamentous covering 
and the dura mater. They are the general recipients for the blood 
of the contiguous structure. They detach a considerable number of 
branches, which run transversely, and anastomose with one another 
on the body of each vertebra, so that each vertebra has its little sys- 
tem of anastomosing branches. These junctions constitute the Cir- 



368 



NERVOUS SYSTEM. 



celli Venosi. These anastomoses communicate with the intercostal 
veins, and, indeed, with all such as are on the outside of the spinal 
column, by means of small branches that get out by the interverte- 
bral foramina. They receive the veins from the bodies of the ver- 
brae, and from the dura and pia mater of the spinal marrow. 

The two sinuses may be traced as low down as the inferior end 
of the sacrum, where they arise by small trunks from the fatty mat- 
ter which surrounds the lower end of the cauda equina. When 
their size is somewhat augmented by their ascent, they communi- 
cate by a large transverse branch. The superior end of each sinus 
terminates by several anastomoses with the vertebral vein, and with 
the anterior occipital sinus: through the latter of which its blood 
is finally carried into the lateral sinus. For a farther account, see 
Sinus Vertebrales. 



CHAPTER II. 



Of the Enceplialon, or Brain. 

By this term is designated that section of the central portion of the 
nervous system, which is contained within the bones of the cranium. 
In its general configuration it differs materially from the medulla 
spinalis, in being spheroidal or oval. It is surrounded by the same 
membranes ; to wit, the Dura Mater externally, the Tunica Arach- 
noidea next, and the Pia Mater internally. 

The Encephalon is formed by cineritious and medullary matter, 
and, as a mass, consists of four distinct portions. The Medulla 
Oblongata, which is a continuation of the spinal marrow, or its 
superior part ; the Protuberantia Annularis, or Pons Varolii, which 
is placed at the upper extremity of the Medulla Oblongata ; the 
Cerebrum, which occupies six or seven-eighths of the cavity of the 
cranium ; and the Cerebellum, which lies upon the posterior fossa? 
of the base of the cranium. As the brain is a double organ, each of 



MEMBRANES OF THE BRAIN. 369 

these parts is symmetrical, or consists in right and left halves peri 
fectly alike. 



SECT. I.— OF THE MEMBRANES OF THE BRAIN, OR 
ENCEPHALON.* 



Of the Dura Mater. 

This membrane, the most exterior of the three belonging to the 
encephalon, lines the whole internal face of the cavity of the era-* 
nium, and is attached with great tenacity to it, particularly in 
early life, from which cause it is considered also as an internal peri-, 
osteum. 

Its external surface has a rough unequal appearance, and adheres 
much more strongly where the sutures exist than on the other sur- 
face of the bones, owing to its detaching many large filaments, 
which penetrate into the sutures and reach to the pericranium. Its 
adhesion to the surface generally of the bones is accomplished by 
fine filaments of fibres, and by very numerous and small blood ves- 
sels which become evident from the dots of blood collected upon it, 
when the bones are torn up, as in the usual manner of examining 
the head. To the base of the cranium, its adhesion is still stronger, 
owing to the abundance of the foramina and fissures there ; to the 
margin of each one of the foramina it is fixed with extreme com- 
pactness, and may be considered as continuous with the adjacent 
pericranium. 

The external surface of the Dura Mater is marked by the arteries 
and veins which creep and ramify through it, and make, as meni 
tioned elsewhere, corresponding furrows in the bones. 

The Dura Mater consists of two laminae, one within the other ; 
they, however, are attached so closely in the greater part of their ex* 
tent, that it requires the knife, or strong artificial force, to separate 
them. Sometimes in tearing off the skull-cap of a middle-aged 
person, the external lamina is brought away with the bone. 

Several processes arise by a duplicature of the internal lamina 

* Anat. Atlas, Figs. 522, 523 to 537, inclusive. 

32* 



370 NERVOUS SYSTEM. 

of the dura mater, and extend from the circumference towards the 
centre of the cavity of the cranium. They are as follows : — 

The Falx Cerebri separates the hemispheres of the brain, and is 
consequently, precisely under the middle line of the head. Its 
shape is well indicated by its name. It commences by a small 
point from the middle of the body of the sphenoid bone, and con- 
tinues to arise along the crista galli, the spine, and middle line of 
the frontal bone, the sagittal suture and the upper limb of the occi- 
pital cross, till it reaches the internal occipital protuberance. It is 
about an inch broad in front, where it begins, but it increases con- 
tinually, though gradually, in breadth till its termination, where it 
is two, or two and a half inches wide. It is strongly fastened along 
the crista galli, and at the foramen coecum ; and being also fastened 
behind' to the tentorium, (with which it is continuous,) as well as 
along the intermediate points of bone, it is kept in a state of strict 
tension, which does not admit of its wavering to one side or to 
the other. Its inferior margin is very concave, and goes to within a 
small distance of the corpus callosum. There are sometimes con- 
siderable apertures in it, through which the flat surfaces of the he- 
mispheres come in contact. 

The Tentorium Cerebelli, another process of the internal lamina 
of the dura mater, is placed transversely across the posterior part 
of the cranium, and separates the cerebellum from the posterior 
lobes of the cerebrum. It is continuous with the posterior end of 
the falx major, whereby these two processes exercise a mutual ten- 
sion. The tentorium is, therefore, kept convex above and concave 
below. 

Its form is crescentic ; its outer circumference is extended along 
the horizontal limbs of the occipital cross, and along the superior 
angle or margin of the petrous bones to the posterior clinoid pro- 
cess. The internal circumference is much smaller and unattached, 
and being placed immediately behind the sella turcica, it leaves an 
opening (the Foramen Ovale) which is nearly of the same size with, 
and occupied by the tuber annulare and the crura cerebri. The an- 
erior extremities of the crescent are continued from the posterior 
clinoid process on each side, to the anterior, so that a deep depres- 
sion is formed for lodging the pituitary gland. 



MEMBRANES OF THE BRAIN. 371 

The Falx Cerebelli is a small triangular process of the dura 
mater, which extends in the middle line from the under surface of 
the tentorium to the posterior margin of the occipital foramen. Its 
base is above, and its point below : the latter terminates by a small 
bifurcation. It adheres by its posterior margin to the middle infe- 
rior limb of the occipital cross ; the anterior margin is free, and 
serves to separate the two hemispheres of the cerebellum. 

The Dura Mater is essentially fibrous, as is sufficiently evident at 
whatever point it may be examined. These fibres have no settled 
course, but cross each other in every direction. It is white, suffi- 
ciently transparent for the vessels of the pia mater to be imperfectly 
seen through it, and almost inelastic. Its internal face is smooth 
and polished, and is covered or lined by the tunica arachnoidea, 
the halitus from which gives it a slippery feel. It is insensible to 
common excitants, such as cutting, or even cauterizing it; from 
which circumstance, together with the common inability of anato- 
mists to trace nerves into its structure, it is supposed, by many, to 
be entirely destitute of them. The learned Chaussier, however, 
takes a different position in regard to these points, and says, that it 
has sensibility, and that though none of the cerebral nerves can be 
traced into it, yet, by attentive examination, it is found, that fila- 
ments from the sympathetic nerve follow the ramifications of its 
middle or great artery.* 

It is well supplied with blood vessels, both arteries and veins. 
The former are derived principally from the branches of the internal 
maxillary of either side, which get into the cranium through the 
foramen spinale and ovale of the sphenoid bone. There are branches 
also from the ethmoidal, the inferior pharyngeal, and the vertebral. 
The branch of the internal maxillary called meningea magna divides 
into two, of which the anterior being the more considerable, gains the 
anterior and inferior angle of the parietal bone; but the other is directed 
backwards across the squamous portion of the temporal. Each of 
these branches is subdivided into a considerable number of smaller 
ones, which for the most part incline backwards, in observing the 
course marked out by the furrows on the flat bones of the cranium. 
When the ramifications become small they then cease to impress the 
bones. Their capillary terminations are supposed by Bichat to be 

* Exposition de L'Encephalc, p. 29. 



372 NERVOUS SYSTEM. 

in small number comparatively, and to be limited principally to those 
of nutrition. 

Some of the veins accompany the arteries, as in other parts of the 
body, and empty into the sinuses about the base of the cranium. 
In the case of both arteries and veins, there are, however, very fre- 
quent anastomoses with the blood vessels of the diploic structure of 
the cranium, and with those of the integuments. 

Of the Sinuses of the Dura Mater. — The sinuses are large cavities 
placed between the two lamina? of the dura mater, and receive the 
blood from the veins of the pia mater. They are formed by the 
separation of these laminae, and are lined by a membrane corres- 
ponding with the internal coat of the veins. 

1. The Sinus Longitudinalis Superior extends along the whole 
base of the falx cerebri, from the ethmoid bone to the tentorium, 
where it terminates in the lateral sinuses. It begins at the foramen 
ccecum in a small pointed manner, and, according to some anato- 
mists, by a small vein, which passes from the nose through this fora- 
men ; it is successively increased in size from before backwards, and 
is of a prismatic shape. One side of the prism is upwards, and, of 
course, is formed by the external lamina of the dura mater ; while 
the other two parietes are lateral, and are formed by the duplicative 
of the internal lamina. Its cavity presents a number of small cords, 
round or flattened, passing from one side to the other; they are called 
Chorda? Willisii or Trabecular, and prevail principally at its back 
part. 

The longitudinal sinus receives on each side from ten to twelve 
large veins, which bring the blood from the pia mater. Those from 
the convex surface of the brain are joined just before entering the 
sinus, by such as belong to the flat side of the hemispheres. These 
veins enter the sinus, for the most part, obliquely forwards, or in a 
manner opposed to its circulation. They are also furnished with 
valves, which circumstance, besides their oblique entrance into the 
sinus, is a provision against their being filled by the regurgitating 
blood. The most posterior ones previously glide eight or ten lines 
between the lamina? of the dura mater, and are somewhat tortuous. 
This sinus also receives several veins from the bones, and some frona 
the scalp, which traverse the bones at different places: among the 



MEMBRANES OF THE BRAIN. 373 

largest of them are those that come through the parietal foramina. 
The dura mater itself sends some of its veins into this sinus. 

Glandulce Pacchioni. In the longitudinal sinus, towards its posterior 
part, is found a considerable but variable number of small granular 
bodies ; some in clusters, others insulated ; and from the size of a pin's 
head to a line or more in diameter. They are the Glandulaa Pacchioni : 
they have no excretory ducts that have been discovered, and it is en- 
tirely uncertain whether any specific fluid is secreted from them. These 
bodies are also to be found on the surface of the dura mater near 
this sinus ; some of them, indeed, make foramina through the dura 
mater, and corresponding depressions in the skull. One on each 
side, larger than usual, and near the parietal foramen, is remarkable 
for this. 

2. The Sinus Laterales, one on each side, are situated in the base 
of the tentorium, and follow its course along the grooves of the oc- 
cipital and parietal bones. They then leave the tentorium and go 
along the groove in the mastoid portion of the temporal bones to 
reach the posterior foramina lacera, where they terminate in the in- 
ternal jugular veins. Their shape is ovoidal, instead of prismatic, 
as the longitudinal sinus is ; they are also larger than it. 

The sinus of the right side is very frequently larger than that of 
the left, and seems to be more a continuation of the superior longi- 
tudinal sinus. In some rare cases one of these sinuses is deficient. 

The lateral and inferior veins of the cerebrum, and the inferior 
veins of the cerebellum run into the lateral sinuses. 

3. The Sinus Longitudinalis Inferior is situated in the falx cere- 
bri just above its concave edge. It is much smaller than the 
superior, and terminates behind in the sinus quartus. It receives 
the veins of the falx, and a few from the corresponding parts of 
the hemispheres. 

4. The Sinus Quartus, or Rectus, is situated in the tentorium, 
where the latter is joined by the falx major or cerebri. It is trian- 
gular or prismatic, and runs from the anterior margin of the tento- 
rium to the posterior, where it terminates in the extremity of the lon- 
gitudinal sinus. The general union which is there formed between 
the longitudinal, the fourth, and the lateral sinuses, constitutes the 
Torcular Hierophili. 



374 NERVOUS SYSTEM. 

The anterior extremity of the fourth sinus, besides receiving the 
inferior longitudinal, is joined by the Vena Galeni, a single trunk, 
formed by the junction of the two veins of the middle of the velum 
interpositum, and extending from the posterior margin of the fornix 
to the beginning of the sinus quartus. The Sinus Quartus, in its 
course, also receives the superior veins of the cerebellum, with the 
exception of the most anterior ones, which terminate in the Vena 
Galeni. 

5. The Sinus Petrosi are small cylindrical cavities, and are so 
called from being situated on the petrous bone. There are two 
on each side ; one above and the other below. The former is the 
Superior, and runs from the cavernous sinus along the superior 
margin of the petrous bone to join the lateral sinus, where the latter 
quits the tentorium to descend towards the base of the cranium. 
The other Petrous Sinus is the Inferior. It is larger than the su- 
perior, and arises, also, from the cavernous sinus by its posterior 
margin. It then runs along the fissure between the occipital and 
the petrous bone, leaving its mark on the margin 'of these bones, 
but principally on the former, and then terminates in the lateral 
sinus just above the posterior foramen lacerum. 

6. The Sinus Cavernosi, one on each side, are also formed by 
a separation of the two laminae of the dura mater, though their 
shape is so different from that of the others. They are situated 
at the sides of the sella turcica, and on the body of the sphenoid 
bone. Their cavity is very irregular, and is furnished with a 
number of filaments, which cross in every direction, and give it a 
cellular arrangement. The internal carotid artery and the sixth 
nerve traverse it, but are protected by its lining membrane being 
reflected over them. 

The cavernous sinus anastomoses in front with the circular sinus, 
and behind with the two petrous sinuses and the anterior occipital. 
It receives, in front, the ophthalmic veins ; from above, the ante- 
rior and inferior cerebral veins; and on the sides, some veins from 
the dura mater. 

7. The Sinus Circularis is placed in the sella turcica, and sur- 
rounds the pituitary gland. It is a small cavity which receives the 



MEMBRANES OF THE BRAIN. 375 

veins of this gland, and, as just mentioned, communicates with 
the cavernous sinus. 

8. In the posterior part of the base of the cranium, there are also 
some other sinuses, called, from their position, Occipital. One of 
these, the Anterior, is upon the basilar process of the os occipitis, 
and extends itself directly across the bone, from the hind part of 
one cavernous sinus to the corresponding point of the other; and is, 
therefore, a means of communication between these two cavities. 
Another of these sinuses, the posterior, extends from the region of 
the Torcular Hierophili, or the upper extremity of the lateral sinuses, 
along the base of the falx cerebelli, to the posterior margin of the 
occipital foramen, where it bifurcates, and then goes along the 
margin of this foramen to discharge itself into each lateral sinus at 
the posterior foramen lacerum. 

The smaller sinuses about the base of the cranium, besides the 
outlets mentioned, have collateral ones, which pass at different 
places through the base of the cranium, and run into the branches 
of the internal jugular vein. These communications, as mentioned 
in the account of the veins, were known to Santorini, and are 
called his Emissaries. 



Of the Tunica Arachnoided* 

This membrane is the second of the envelopes of the brain, and 
is spread over the surface of the pia mater, adhering to it closely in 
the greater part of its extent. It is so diaphanous and thin, as its 
name implies, that it is distinguished with some difficulty, wherever 
it adheres to the pia mater ; which it does all over, With the excep- 
tion of a few places on the basis of the brain, as, for example, 
just in front of the tuber annulare, and behind the medulla oblon- 
gata. There this membrane may be seen stretched from one pro- 
minence to another, and separated considerably from the pia mater. 
It does not dip into the fissures of the brain, but goes directly across 
them, from the ridge of one convolution to that of the adjacent, so 
that it is entirely smooth and uniform in its distribution. Notwith- 
standing the general closeness of its connexion with the pia mater, 
it may yet be separated from it by careful dissection, by slight 



376 NERVOUS SYSTEM. 

maceration, or by the use of the blow-pipe ; dropsical effusions fre- 
quently make out the distinction between the two membranes ; also 
the deposite of coagulating lymph. 

Considering this membrane as a single layer, we have to speak 
of the dura mater, as lying loosely upon it. But the authority of 
Bichat sanctioned by the testimony of many other anatomists, has 
assigned to it a much more considerable extent. For it seems to 
be well ascertained, both by analogy and by observation, that it is 
a sac ; which besides covering the external surface of the pia mater, 
is reflected over the internal surface of the dura mater, and gives 
to the latter its smooth shining appearance.* This lining is<on the 
same principle that the serous lamina of the pericardium lines its 
fibrous lamina, or that the synovial membrane lines the ligamentous 
attachments of an articulation. In the early periods of life, it may 
be separated from the dura mater, by dissection. Vicq. D'Azyr 
has related a case in which it was detached by a collection of pus. 
Its places of reflection to the dura mater are on the basis of the cra- 
nium, where the blood vessels and nerves pass into the sheaths 
formed by the dura mater, and along the blood vessels entering into 
the sinuses. This membrane is continuous with the tunica arach- 
noidea of the medulla spinalis. 

The tunica arachnoidea is considered to pass into the ventricles 
of the brain by the same apertures that the pia mater does, but it is 
much less manifest there than elsewhere. f 

The texture of this membrane is exceedingly delicate and fine. 
It is always found, in health, in a transparent state, and is not fur- 
nished with red blood vessels, but nerves are considered by Pur- 
kinje to exist in it. It secretes a sort of halitus, or synovia, which 
facilitates the motions of the brain, and prevents it from adhering. 
Occasionally, this secretion is so much augmented as to constitute a 
genuine dropsy. 

* There are some excellent and unequivocal examples of this in the Wistar Mu- 
seum, prepared by the Author. 

j- As the ventricles of the encephalon are but fissures in its structure, this ar- 
rangement is in opposition to that of the fissures on the surface of the encephalon, 
and in fact may be doubted from its defective evidence, excepting in the case of the 
Velum interpositum. 



MEMBRANES OF THE BRAIN. 377 



Of the Pia Mater. 



The Pia Mater, or Tunica Cerebri Vasculosa, is in contact with 
the substance of the brain. It also is extremely delicate, but, un- 
like the last, is furnished with an immense number of blood vessels 
which go to or return from the brain, and are, in most subjects, so 
abundant that they give a florid appearance, at a little distance, 
to the whole membrane. Its external face appears entirely smooth, 
owing to its being covered, and its processes cemented together by 
the tunica arachnoidea ; but its internal face exhibits these pro- 
cesses as penetrating to the bottom of the fissures of the brain ; con- 
sequently, it is very unequal. 

The pia mater presents, along the course of the longitudinal sinus, 
an abundance of those small graniform bodies, existing also in this 
sinus, and called Glanduke Pacchioni. They beset the veins as they 
enter into the longitudinal sinus, and even follow them there, so that 
there is a chain of them from the surface of the pia mater, into the 
sinus. They are frequently so abundant on the superior part of the 
hemispheres, near the great fissure, that they cause the dura and pia 
mater to adhere, as if from inflammation. It is the larger of this 
kind which frequently produce an absorption of the dura mater, and 
of the internal table of the skull. These bodies are also found, along 
with the pia mater, in the ventricles of the brain, as at the external 
margin of the plexus choroides, around the pineal gland, and at the 
bottom of the fourth ventricle. 

The Glandulse Pacchioni, wherever found, present a similar ap- 
pearance and structure, but varying much in size : they are generallv 
in clusters, which repose on common bases. Anatomists differ much 
in their opinion concerning them. Bichat acknowledges his com- 
plete ignorance on the subject; Portal says that they are only con- 
geries of vessels or of cellular bodies filled with fat. Meckel states, 
that as they are found especially in the later periods of life, and 
never before birth, and as they never exist in very great abundance, 
except in persons who have often experienced diseases of the head, 
and are not observed in any animal ; so we are forced to consider 
them as morbific productions, and not, as Pacchioni conceived, 
glands whose excretory ducts opened into the ventricles of the brain 
and into the sinuses of the dura mater. 
Vol. II.— 33 



378 NERVOUS SYSTEM. 

The Pia Mater covers the upper surface of the cerebrum with such 
uniformity as not to require a detailed description of it ; where it sinks 
into the great fissure between the hemispheres, it adheres from the 
two sides just above the corpus callosum. On the basis of the brain, 
it penetrates deeply into the anterior fissure, or the Fissura Sylvn ; 
is reflected over the inequalities of the brain, but never in such a 
way as to leave them ; and secures the bottom of the third and of the 
fourth ventricle. 

The distribution of the pia mater, over the ventricles of the brain, 
is more complicated than that over its periphery, and it may be re- 
marked, that this portion is called, by some anatomists, the Internal 
Pia Mater ; that its texture is much more delicate, and net-like, and 
that it adheres more closely to the subjacent parts. Being extended 
from the superior surface of the Cerebellum and of the Pons Varolii, 
it enters into the third ventricle, under the posterior margin of the 
fornix, by the large transverse fissure between the latter and the 
tubercula quadrigemina. By its course between the fornix and tha- 
lami, it constitutes the Velum Interpositum, or the Tela Choroidea 
of Vicq. D'Azyr. The pia mater is also introduced into the inferior 
cornu of the lateral ventricles along the internal margin of the hippo- 
campus major, at the side of the pons varolii; and into the fourth 
ventricle from its bottom part. 

The several plexuses of vessels found in the ventricles of the brain 
have for their basis the pia mater ; which is there arranged into a 
great number of folds, some of them being longitudinal and others 
crossed. Their formation, according to the new views which have 
been taken of the development and growth of the brain, by Tiede- 
mann, depends upon the internal membrane of the brain contracting 
itself as it finishes the deposite of medullary matter called Centrum 
Ovale. The vessels of the plexuses are the arteries, which are spent 
upon the surface of the ventricles, and the veins derived from the 
same ; the latter are much more numerous than the first. 

Of the Structure of the Pia Mater. — The pia mater is commonly 
spoken of as a complete membrane, yet its structure is different from 
that of membranes generally, inasmuch as it is a net-work, the meshes 
of which are formed by arteries and veins, and the interstices filled 
up by a loose, weak cellular substance. Bichat has very justly ob- 
served, that the union with the tunica arachnoidea is solely on the 



THE MEDULLA OBLONGATA. 379 

part of this cellular substance ; whereas, the union with the cerebrum 
is confined to the vessels, which are extremely numerous and very 
small before they penetrate it, and appear as bloody points when we 
cut into the substance of the brain. The principal arterial trunks of 
the pia mater, being the internal carotids and the vertebrals and their 
branches, are at the basis of the brain; these trunks divide into 
smaller branches, on the convolutions and in the fissures. The 
primary divisions again divide and subdivide into tubes not much 
exceeding the size of the capillary vessels. In this last state they 
enter the brain and may be seen very readily, either by a fine in- 
jection, or by tearing up the pia mater. Purkinje is said to have 
traced nerves into it.* 



SECT. II. — OF THE MEDULLA OBLONGATA.f 

According to the usage of the best authorities of the present day, 
who follow in the description of the central parts of the nervous sys- 
tem, the order of their development in the human subject, and also 
of their appearance in animals, I shall describe the encephalon from 
below upwards instead of from above downwards. The preference 
thus shown is, perhaps, principally serviceable in fixing upon the 
mind the order of growth and appearance, which, according to 
well established experiments, are exactly in the order of importance 
to life. 

The Medulla Oblongata, also called Bulbus Rachidicus, ex- 
tends from the superior margin of the first cervical vertebra to the 
middle of the basilar process of the os occipitis. It becomes gra- 
dually larger as it ascends, and is about an inch in length, and eight 
lines wide at its base. It is by no means so cylindroid as the me- 
dulla spinalis, but presents several risings and depressions on its 
surface. 

The under surface of the Medulla Oblongata is divided longi- 
tudinally by the middle fissure, a continuation of that on the front of 
the Medulla Spinalis. The fissure is two or three lines deep, which 
is rendered manifest by removing the pia mater. The Corpora Py- 
ramidalia are placed one on either side of it, and are oblong bodies ; 

* See Serous Membranes. t Anat. Atlas. Figs. 524, 523, 529, 530. 



3S0 NERVOUS SYSTEM. 

being a continuation of the cords that decussate from the opposite 
sides of the spinal marrow. These bodies occupy the whole length 
of the Medulla Oblongata, increase in breadth as well as in eleva- 
tion during their ascent, and are, lastly, somewhat constricted or 
diminished abruptly, where they join the Protuberantia Annularis or 
Cerebralis. Precisely at the latter point, between their bases, is a 
deep triangular pit, into which penetrates the pia mater. J. F. 
Meckel says that they are united at their lower extremities by a 
small transverse medullary Commissure of a line and a half in 
breadth. This junction is above the decussation of the cords from 
which the corpora Pyramidalia arise. 

The Eminentise Olivares are two bodies ; one on either side, at 
the external margin of the corpus pyramidale. They are about 
seven lines long: two and a half wide, and are elevated to the 
height of one line. The elevation ceases somewhat short of the an- 
nular protuberance, but their interior structure is continued into the 
latter, and may be traced into the thalamus nervi optici. 

Like the pyramidalia, those bodies are medullary externally ; but 
within, there is a nucleus of cineritious matter, called, from the irre- 
gularities of its margin, Corpus Fimbriatum, and which encloses 
some medullary matter. The corpus fimbriatum is open at the inner 
circumference, and has the medullary matter which it contains, conti- 
nuous there with the substance of the corpus pyramidale. Below, its 
circumference is continuous with the cineritious matter of the me- 
dulla spinalis. In the slight depression between the corpus pyra- 
midale and the eminentia olivaris, are the roots of the hypoglossal 
nerve. 

The Corpora Restiformia, also one on either side, are placed at 
the lateral posterior margins of the medulla oblongata, just posterior 
to the eminentiae olivares ; and are readily brought into view by ele- 
vating the contiguous parts of the cerebellum. They are oblono- 
risings of an inch in length ; their lower extremities are in contact, 
and project where they begin to arise from the borders of the pos- 
terior fissure of the medulla oblongata ; they then diverge, and 
extend forwards and upwards to terminate above in the cere- 
bellum. 

The corpus restiforme is formed of medullary matter, and is a 
continuation of the posterior cord of the medulla spinalis. From 



THE MEDULLA OBLONGATA. 381 

its superior posterior margin a thin medullary lamina of about three 
lines square arises, and being sustained by the pia mater, advances 
to meet its fellow, but does not absolutely touch it.* From the an- 
terior margin of each corpus restiforme there departs a second pro- 
cess of medullary matter, larger and more thick than the preceding, 
and being covered by the roots of the pneumogastric and glosso- 
pharyngeal nerves, adheres to the plexus Choroides of the fourth 
ventricle. 

The superior face of the medulla oblongata is excavated between 
the corpora restiformia, in such a way as to present the outline of 
a writing pen, and is therefore, called Calamus Scriptorius ; which 
forms a considerable part of the floor of the fourth ventricle of the 
Brain, or the sinus rhomboideus. The fissure, in its middle, cor- 
responds with the slit of a pen, the nib being downwards ; and the 
fissure extends from the posterior fissure of the medulla spinalis the 
whole length of the medulla oblongata. 

The calamus scriptorius is marked by several streaks of medullary 
matter, which extend themselves transversely with a very slight de- 
gree of obliquity upwards, and reach the external margin of the 
corpus restiforme of the corresponding side. These medullary striae 
present some varieties in regard to their volume, number, and ar- 
rangement. Sometimes they are slightly elevated narrow lines, 
which are perfectly distinct from each other, and from one to four- 
teen in number. On other occasions their volume is greater, but 
they are not so numerous. They generally extend, either one or all, 
from the middle fissure to the commencement of the auditory nerve, 
and are thereby a part of its origin. Sometimes the anterior ones 
are directed towards the origin of the trigeminus nerve, but their 
union with it is not yet ascertained ; the posterior ones are sometimes 
blended with the radical filaments of the pneumogastric nerve. The 
strise themselves, are sometimes interwoven or blended, and pass 
the boundary of the middle fissure to join with those of the other 
side. Their roots may be traced along the middle fissure, to the 
front or under surface of the medulla oblongata. If a medulla ob- 
longata be well hardened in spirits of wine and then torn open through 
its middle fissures, the surface thus exposed presents itself as formed 
almost entirely of the filaments just mentioned, running from back 
to front. In some cases I have seen them at their anterior ends pass 

* Called Pons Sinus Rhomboidei by J. F. Meckel. 



382 NERVOUS SYSTEM. 

on so as to form a superficial layer encircling the front of the medulla 
oblongata like threads wound around a bunch of rods. Meckel, 
whose observations on this subject are highly interesting, is disposed 
to consider the striae not only as forming the roots of the auditory 
nerve, but as also related closely to the trigeminus and to the pneu- 
mogastric. 

On the surface, also, of the fourth ventricle, or sinus rhomboi- 
deus, but in advance of the preceding striae, there is another, on 
each side, still larger, which may be distinguished by its always be- 
ginning at some distance from the middle fissure. Its direction is 
transverse, and it passes just above the anterior extremity of the 
corpus restiforme, to run into, or to assist in forming, the root of the 
auditory nerve. Its existence is much more constant than that of 
the others. It is considered as an assistant ganglion to the auditory 
nerve, and in cases of deafness has been deficient. Being principally 
"ineritious, it is called Fasciola Cinerea. 

In tracing the continuation of the structure of the medulla spinalis, 
into that of the medulla oblongata, we find that each of the anterior 
cords of the medulla spinalis, besides crosssing with some of its 
fasciculi at the place mentioned, to wit, at the decussation of Misti- 
chelli, and continuing their course upwards to form the corpus pyra- 
midale, sends off a larger fasciculus, which ascends behind the emi- 
nentia olivaris, and forms the floor of the fourth ventricle or sinus 
rhomboideus. There is yet another fasciculus of white matter, ac- 
cording to Rosenthal, between the others, into which the anterior 
column of the medulla spinalis is divided. He says, that it touches 
the eminentia olivaris, surrounds it, and, after having traversed the an- 
nular protuberance, terminates in the tubercula quadrigemina. 

The posterior cords of the Spinal marrow, being continued into 
the corpora restiformia, become still more evidently divided into 
two fasciculi, from an increase of their volume, than they were in the 
vertebral canal. The internal of these fasciculi stops, by a pointed 
termination, near the borders of the sinus rhomboideus, or fourth ven- 
tricle of the Brain ; while the external is continued on through the 
annular protuberance to the cerebellum. 



PROTUBERANTIA ANNULARIS. 383 



SECT. III. — PROTUBERANTIA ANNULARIS.* 

The Annular Protuberance (Protuberantia Annularis, Modus 
Cerebri, Pons Varolii) is the large projecting body, placed near the 
centre of the base of the encephalon, at the top of the medulla ob- 
longata, and upon the junction of the body of the sphenoid bone 
with the basilar process of the os occipitis. It is convex, and about 
an inch in diameter, its transverse measurement being a line or two 
larger than the other. It is divided by a superficial fossa into two 
symmetrical halves, right and left. 

When the pia mater is removed from the Protuberantia Annu- 
laris, the under surface of the latter is seen to be formed by trans- 
verse medullary fibres which come from the crura cerebelli. When 
these, which are commonly one or two lines in depth, are removed 
by scraping or cutting, a cineritious matter is exposed, which is tra- 
versed by numerous layers of medullary matter, also going in a 
transverse direction. About two lines deep from the surface of the 
protuberance, near the middle of each of its halves, are found some 
longitudinal medullary fibres connected with cineritious matter, and 
which may be fairly traced as a continuation of the filamentous 
structure of the pyramidal bodies. These fasciculi, or filaments, 
passing on through the protuberance, are continued so as to form 
the under surface of the crura of the cerebrum. 

Lying still deeper than the medullary fibres alluded to, there is 
an accumulation of cineritious matter, intermixed with perpendicular 
medullary layers situated one behind the other. Behind (or above 
when we stand erect) this intertexture, a small fasciculus (the cord 
described by Rosenthal) of medullary matter exists, which is a con- 
tinuation of the intermediate fasciculus of the anterior medullary 
cord of the medulla spinalis, and may be traced afterwards to the 
superior face of the crus cerebri, where it terminates as alleged by 
Rosenthal, in the Tubercula Quadrigemina. 

At the centre of the posterior margin of the Pons, we find some- 
times an elongated triangular process, which penetrates deeply be- 
tween the bases of the Pyramids, and may be traced to the posterior 
middle fissure of the Medulla Oblongata. 

* Anat. Atlas, Figs. 52 4-53L 



384 NERVOUS SYSTEM. 



SECT. IV. — OF THE CEREBELLUM. 



* 



The Cerebellum, being placed in the posterior fossa? of the cra- 
nium is separated by the tentorium from the posterior lobes of the 
cerebrum, beneath which it lies. It is connected with the Pons 
Varolii by a trunk of medullary matter on each side, called the Crus 
of the Cerebellum ; and which is a root of the medullary matter 
entering into the composition of the pons. 

It is of a rounded form, and well fitted to the cavity in which it 
reposes. It is convex above and below; measures about four 
inches in its transverse diameter, two and a half in thickness, and 
about the same from before backwards. The upper face is divided 
into two equal parts or halves, by a middle ridge, while the lower 
face is divided in the same way by a fossa. These halves are called 
hemispheres ; their surface is marked by many horizontal and trans- 
verse fissures, the edges of which are kept closed by the adhesion of 
the pia mater. 

The fissures are interposed between the laminse. or convolutions 
of the cerebellum, which for the most part converge towards its 
medullary trunk ; the larger fissures are behind, while the shortest 
are in front near the annular protuberance. The pia mater pene- 
trates to the bottom of these fissures, some of which, when exposed 
fully by its removal, are found to extend to the depth of an inch or 
more. One of these fissures which exists on the superior surface of 
the cerebellum, half an inch distant from the posterior and external 
margin of the latter, has a circular course, and is so well-marked by 
its size and depth that it is called the Sulcus Superior Cerebelli. 
Another, situated under similar circumstances on the inferior surface 
of the cerebellum, is called the Sulcus Inferior Cerebelli. On the 
latter surface, also, there are two or three more of a middle size, 
situated between the sulcus inferior and the annular protuberance. 
These larger sulci have given occasion to anatomists to multiply 
most unreasonably the number of lobes of which the cerebellum 
consists. Bichat's mode of description is preferable : he says, that 
by cutting (vertically) through one of the hemispheres of the cere- 
bellum, so as to expose the thickest part of its medullary matter, six 
or seven principal fissures will be seen, which, by penetrating to a 

* Anat. Atlas, Figs. 525 to 531, inclusive. 



THE CEREBELLUM. 



385 



considerable depth, divide the cineritious portion into as many con- 
verging parts. In the interior of these fissures there are much 
smaller ones, which pass at right angles to them. On the surface 
or periphery of the cerebellum, in the intervals of the larger fissures, 
there are many small ones, which, though nearly horizontal, termi- 
nate in each other by acute angles. 

The superior middle ridge of the cerebellum, from its shape and 
position, is called, by Vicq. D'Azyr, Vermis Superior ; the anterior 
extremity of which, from its elevation, is the Monticulus Cerebelli. 

The middle inferior part of the cerebellum, which presents the 
deep sulcus running longitudinally and forming the division into 
hemispheres, has a long ridge occupying the sulcus. This ridge 
is the Vermis Inferior of Vicq. D'Azyr and is so concealed by the 
adjacent portions of the hemispheres, that a good view of it can be 
got only by removing the arachnoidea, the pia mater and pushing the 
hemispheres aside. The transverse fissures which penetrate it, and 
its general irregularity of, surface, will then be sufficiently distinct. 
The pia mater and arachnoidea pass from the fore part of this body 
to the medulla oblongata, and thus assist in forming the floor of the 
fourth ventricle ; which, without this reflection would be exposed. 
The central part of the cerebellum as formed by the vermis superior 
and by the vermis inferior, is the Fundamental Portion of Gall and 
Spurzheim. 

At the root of the crus cerebelli are two small protuberances; the 
one below it, in the erect position, is the Lobulus Amygdaloides, 
and the other the Lobulus Nervi Pneumogastrici. 

The substance of the cerebellum, is formed of cineritious matter 
externally, and of medullary matter internally. When a vertical 
section of it is made through the middle of one of its hemispheres, 
the medullary neurine or matter puts on the appearance of the thuya 
or arbor vitas, the roots and ramifications of whose limbs, even to 
their smallest extremities, are surrounded by cineritious neurine or 
matter. In this view, there appears to be more cineritious than 
white matter ; but when a horizontal cut is made from the periphery 
to the centre, parallel with one of the deep concentric fissures, the 
proportion of medullary matter seems to be much more considerable ; 
and the arbor vita? arrangement is proved to depend upon the laminae 
of medullary matter radiating from the centre, or, in other words, 
from the massive medullary trunk in the interior of the hemisphere 
of the cerebellum. Each of these radiations commences by a root 



386 NERVOUS SYSTEM. 

of considerable size, which divides and subdivides into branches. 
Each primitive radiation, as well as its branches, is covered by its 
own layer of cineritious matter about one line in thickness, and is 
kept perfectly distinct from the contiguous ones by the fissures which 
extend internally from the periphery of the cerebellum. 

In the middle of the trunk of the arbor vitse, exists the Corpus 
Rhomboideum, or Dentatum. It is an oblong rounded body, jagged 
and cineritious in its circumference, but medullary within. Its con- 
figuration resembles that of the corresponding body in the eminentia 
olivaris, with the addition of its being larger, and having its outline 
better marked. It is the ganglion of the cerebellum of Gall and 
Spurzheim. 

The Valve of Vieussens (Velum Medullare, Valvula Cerebelli or 
Cerebri) arises from the cerebellum, just under the anterior part of the 
base of the monticulus, and runs obliquely upwards to terminate in the 
testes. Sometimes is it marked in its middle, by a longitudinal line or 
slight fissure, from either side of which proceed small lateral ones. It is 
principally medullary, and has a small quantity of cineritious matter 
at its extremities. It is thinner in the middle than at either of its 
margins. 

The Central or Fundamental Portion of the Cerebellum exhibits 
also very clearly the arborescent arrangement, and is furnished with 
about seven primitive radiations, coming from a medullary trunk. 
The proportion of medullary matter to cortical, is less in it than in 
the hemispheres of the cerebellum. Each of the primitive radiations 
may be traced to some particular point or prominence on the surface 
of the fundamental portion, thus forming its basis ; but this study is 
more curious than useful, though several anastomists have pur- 
sued it. 

Three medullary fasciculi, on each side, have now been assigned 
to the cerebellum ; one of these is the continuation of the corpus 
restiforme of the medulla oblongata; a second is the valvula cerebelli ; 
and the third, the Cms Cerebelli, which joins the annular protuber- 
ance. The first two fasciculi belong to the middle or fundamental 
portion of the cerebellum ; they are consequently, situated more in- 
ternally, and are partially concealed by the cms cerebelli, and have 
interposed between them and the latter, the Corpus Rhomboideum 
or Dentatum. 



THE CEREBRUM. 387 



SECT. V. — OF THE CEREBRUM.* 

The Cerebrum weighs about three pounds, and is seven times as 
heavy as the cerebellum. It is ovoidal, and measures about six 
inches in its antero-posterior diameter, five inches in its greatest 
breadth, which is behind, and four or five in depth. It is separated 
above by a deep fissure, (Fissura Longitudinalis,) into two equal 
parts, called Hemispheres. At the bottom of this fissure by sepa- 
rating the contiguous surfaces of it, is to be seen a broad lamina of 
medullary matter passing from side to side, and called the Corpus 
Callosum, which connects the two hemispheres together. The under 
surface of each hemisphere is subdivided into three lobes ; Anterior, 
Middle, and Posterior. 

The anterior lobes are placed upon the anterior fossae of the base 
of the cranium ; the Middle, upon the middle fossae of the same ; and 
the Posterior Lobes rest upon the tentorium. The two anterior lobes 
are completely separated by the Fissura Longitudinalis, which ex- 
tends between them to the base of the cranium ; the same is the case 
with the posterior lobes ; the middle lobes have interposed between 
them the annular protuberance and the crura cerebri. When the 
pia mater is removed, the anterior lobe is seen to be marked off from 
the middle lobe by a deep sulcus, the fissure of Sylvius, in the under 
surface of the cerebrum, corresponding, in its position, with the pos- 
terior margin of the Lesser Sphenoidal Wing. The boundary be- 
tween the middle and the posterior lobe is, by no means, well de- 
fined on the basis of the brain, but it is agreed to consider as pos- 
terior lobe, all that part of the hemisphere which rests upon the ten- 
torium. 

The periphery of the cerebrum is formed into convolutions,! ( Gyri) 
which give it an unequal tortuous surface, resembling the intestines 
of a small child. These convolutions are separated by fissures (Sulci) 
of depths varying from an inch to two inches or more. The con- 
volutions proceed in diversified and complicated courses, which 
never correspond in different individuals, and seldom exactly on the 
two hemispheres of the same brain. Though their summit is gene- 
rally convex, yet some of them have it depressed slightly, which is 

* Anat. Atlas, Figs. 543 to 547, inclusive. 
t Anat. Atlas Fig. 532, &c. 



388 



NERVOUS SYSTEM. 



considered a proof of each convolution being divisible into two 
halves or layers, placed side by side. Some of the convolutions are 
short, others long; they present numerous varieties in the manner 
of joining each other. Owing to the narrowness of the fissures be- 
tween them, they are closely packed together, so that the lateral sur- 
faces of each one are suited to such as are contiguous; occasionally, 
there is a departure from this rule. 

The surface of the convolution, by which we mean not only the 
most exterior periphery of the cerebrum, but also the surface formed 
by the fissures to their very bottom, is covered by cineritious neurine 
or matter of about one or two lines in thickness. 

Within the periphery of the cerebrum, the mass of medullary 
neurine or matter is very considerable, and is of an ovoidal shape. 
This ovoid is called the Centrum Ovale of Vieussens, and is brought 
fairly into view by making a horizontal cut through the hemispheres, 
two inches below their summit. 

In proceeding with the anatomy of the cerebrum from its base 
upwards, the following is the order or succession of parts in its 
structure:* In advance of the pons varolii, and springing from it, 
there are two divergent medullary trunks, one on each side, which 
run forwards, and are lost in the medullary substance of the cere- 
brum. These trunks are the crura cerebri, upon the upper surface 
of each are two protuberances : the posterior is the thalamus nervi 
optici, and the anterior is the corpus striatum. Each cms cerebri, 
having penetrated into the substance of its respective hemisphere, 
expands by a multiplication of the filaments composing it, so as to 
constitute the principal bulk of the hemisphere. These filaments 
may, indeed, be traced very satisfactorily in almost every direction 
towards the periphery of the cerebrum, where they terminate in the 
convolutions, their extremities being covered by the cineritious 
matter there. The arrangement is best seen by scraping with a 
knife along the base of the brain, especially when the latter has been 
hardened in spirits of wine, and it is constituted by what are called, 
by MM. Gall and Spurzheim, the diverging fibres of the brain. 

The point is not, indeed, entirely settled that the diverging filaments 
end in the convolutions, or do not rather afterwards inflect or double 
on themselves, and pass inwards again to the middle line of the brain, 

* Anat. Atlas Figs. 534, 536. 



THE CEREBRUM. 389 

forming, by their convergence, the corpus callosum. At all events, 
the fact is quite demonstrable, that as the under and lateral portions 
of the hemispheres consist in diverging filaments, arising in and from 
the crus cerebri, so the upper portion and the corpus callosum, con- 
sist in filaments which arise in the adjoining convolutions, and collect 
towards the middle line of the corpus callosum, where they adhere 
to the congeneric filaments of the other side. 

The arrangement, in the most simple conception and illustration 
of it, would be exemplified by folding a strip of cloth double on 
itself, so as to convert it into a loop ; the under part of the loop 
would then represent the diverging fibres of the cerebrum and the 
upper part the converging fibres, or corpus callosum: it being at 
the same time borne in mind that the continuation of the two orders 
of fibres into one another in the brain, is not so fully ascertained as 
would be represented by this model. 

Between these two orders of fibres there is a horizontal cleft or 
interval. This interval is the lateral ventricle of the hemisphere, 
which may be got into under the posterior margin of the corpus 
callosum, from its being open there, or rather only closed by an ad- 
hesion of the membranes, which is easily lacerated. 

The preceding is intended as a mere outline or base of the de- 
scriptive anatomy of the cerebrum. The following, therefore, may 
be considered as the detailed account : — - 

The Crura Cerebri are rounded below ; are about eight lines 
long, and increase in their transverse diameter as they advance ; 
their vertical diameter is about ten lines. They mutually diverge, 
beginning from their roots, and are separated by a deep fissure*, 
considered as a repetition of that on the front of the medulla ob- 
longata. Above this fissure is the third ventricle of the brain, which 
itself is a repetition of the middle fissure on the posterior face of the 
medulla oblongata. The surface of the crura is marked by super- 
ficial furrows, running longitudinally ; and about two lines before 
the tuber annulare, by a transverse fasciculus of medullary matter or 
white neurine, very slightly elevated : the optic nerves also cross 
them obliquely at their fore part. 

In regard to texture, the crus cerebri presents, on its under sur- 
face, a medullary layer of two lines in thickness ; to this succeeds 
a parcel of cineritious matter, which, on being removed, is followed 

Vol. II.— 34 



390 NERVOUS SYSTEM. 

by a mixture of both cineritious and white matter, more abundant 
than either of the preceding. 

The Tuber Cinereum, or Pons Tarini, is a portion of the under 
surface of the crura cerebri, at the floor of the third ventricle. It 
is continuous in front with the anterior margin of the corpus cal- 
losum, forms the floor of the third ventricle, and is composed, as its 
name implies, of cineritious neurine. 

The Eminentiae Mammillares, or Corpora Albicantia, are two 
small bodies, one on each side, about the size of a French pea. 
They are situated near the anterior extremities of the crura cerebri, 
on their internal faces, and almost in contact with each other. Their 
texture is medullary without, and cortical within. 

The Infundibulum is placed immediately before the eminentiae 
mammillares. It is a flattened conoidal body, half an inch long, 
with its base upwards, and its apex going downwards and forwards. 
It is formed of cineritious matter. Most generally its base is hol- 
low, and opens into the third ventricle, but its point is closed. J. F. 
Meckel, however, asserts that a communication exists entirely through 
it, from the pituitary gland to the third ventricle, and that he has 
frequently proved this by passing air or liquids from the gland, though 
the experiment does not succeed when he attempts the injection 
from the third ventricle. 

In front of the infundibulum the optic nerves unite, after having 
crossed obliquely the crura cerebri from without inwards and for- 
wards. In this passage, where they reach the middle of the crura, 
and at the internal border of the same, they come in contact with 
the tuber cinereum, from which they get a few filaments ; but of 
this, more hereafter. 

The Pituitary Gland (Glandula Pituitaria) is situated in the Sella 
Turcica, and is covered so completely by the dura mater, that only 
a small aperture is left for the point of the infundibulum to pass 
through and to adhere to it. It is an ovoidal body^ the greatest dia- 
meter of which is transverse, and amounts to six lines. It is par- 
tially divided, so as to give the appearance of two lobes, of which 
the anterior is much the larger. It is hard and cineritious, with a 



THE CEREBRUM. 391 

small quantity of medullary matter within. In either side of it there 
is a depression from which leads a small canal towards the place 
where the infundibulum joins it ; the two canals are, in the latter 
place united into one. In some very rare cases, gritty matter has 
been found in it, as there is in the pineal gland. It is also sur- 
rounded by pia mater. 

The Thalami Optici, called, by Gall, the Posterior Ganglions of 
the brain, [Ganglia Postica,) are amongst the most conspicuous 
parts of the internal structure of the cerebrum, and are two in 
number, one for either side. They are situated on the superior face 
of the crura cerebri, are about an inch and a half long from behind 
forwards, and about eight or ten lines broad and deep. 

The thalami are convex above and internally. At the junction 
of these two surfaces is observed a medullary line, described under 
the name of peduncle of the pineal gland. Their posterior extre- 
mity is likewise convex, and is divided into three rounded promi- 
nences : one is above the other two, and is the Tuberculum Posterius 
Swperius; the second is below and within, (Corpus Genicuhtum In- 
ternum,) and the third is below and external, (Corpus Geniculatam 
Externum.) There is a fourth tubercle (Tuberculum Anterius) 
which is situated in front on the upper convex surface of the thala- 
mus ; it is produced by the fan-like termination of a large medullary 
fasciculus which comes from the eminentia mammillaris. 

The thalami are somewhat flattened on the middle of their con- 
vex internal surface, and adhere there to each other by a layer of 
cineritious substance, called Commissura Mollis. When the brain 
is very slightly advanced in putrefaction, or has been made soft by 
dropsy, this junction scarcely seems to exist at all. 

The thalami are medullary on the surface presented to the ven- 
tricles of the brain, but within they are a mixture of cineritious with 
medullary matter. The fibres of the medullary are very intimately 
blended with the crura cerebri, and radiate from within towards the 
circumference of the brain : some of them are placed in layers, and 
are connected with the tubercula quadrigemina. 

The Tubercula Quadrigemina (or the Nates et Testes) are situ- 
ated on the superior face of the crura cerebri, and just behind the 
thalami nervorum opticorum. A very complete view of them is 
obtained by separating the posterior lobes of the cerebrum, and by 



392 NERVOUS SYSTEM. 

paring off the vermis superior cerebelli. Though the name implies 
four distinct prominences, yet they are formed from a common mass 
of nine or ten lines square, on the posterior surface of which these 
prominences arise. They are in pairs, and are separated from one 
another by a crucial depression. The largest, or upper pair, is the 
Nates, the lower pair the Testes. The external surface of these 
bodies is medullary, and within they are cineritious. From the 
Nates there proceeds a considerable medullary fasciculus, which 
runs forward to join the Corpus Geniculatum Internum on the in- 
ternal posterior face of the thalamus nervi optici ; there proceeds 
also from them a second fasciculus, which either joins the optic 
nerve itself, or the contiguous part of its thalamus. The Testes 
receive, at their lower end, the valve of the brain ; and there also 
proceeds from them a large fasciculus of medullary matter, which 
joins the Corpus Geniculatum Externum of the optic thalamus. 

The Corpora Striata, or the Ganglia Cerebri Antiea, also two in 
number, one for each side or hemisphere of the brain, are situated 
before the thalami optici, at the bottom of the lateral ventricles. 
They are about two and a half inches long, convex on their upper 
surface, and eight lines broad at their front part, but taper very gra- 
dually to a point behind. They are about four lines apart in front, 
and are separated there by the septum lucidum, but their posterior 
extremities diverge from each other, so as to admit the thalami optici 
between them. 

The surface of the corpus striatum is cineritious, but within it 
consists of cineritious and of medullary matter, placed in layers 
which alternate with each other. These layers are arranged in a 
crescentic manner, so as to present the convexity upwards and the 
concavity downwards. The medullary substance is a continuation 
of that of the cms cerebri and of the optic thalamus. It enters at 
the posterior inferior part of the corpus striatum, and immediately 
divides into three layers, placed one above the other, and of which 
the two inferior are more narrow and short than the superior. The 
upper layer, in its progress forwards, is interrupted by a body of 
cineritious substance, which occasions it to divide into a multitude 
of distinct radiated fibres. The same circumstance attends the other 
layers, but in a more limited degree. The medullary matter of the 
corpus striatum may then be traced, in all directions, into the hemis- 
phere of the brain. The cineritious substance of the corpus striatum 
is abundant, and is divided by some anatomists into two kinds, one 



THE CEREBRUM. 393 

of a light gray, and another of a darker colour. The first forms the 
middle and inferior part of the corpus striatum ; the second is in 
greater quantity, and is found principally above and between the 
two upper layers. Such is the general plan of the structure of the 
corpus striatum ; but, it should also be understood, that a close in~ 
tertexture exists between its medullary and cineritious matter. 

The most satisfactory way of exposing the structure of the corpus 
striatum, is to scrape off its under surface, in tracing its medullary 
matter from the crus of the cerebrum, and through the optic thala- 
mus. It will then be seen, that the medullary substance of the crus 
reaches the posterior inferior part of the corpus striatum, and is imme- 
diately invested in the greater part of its circumference with cineritious 
matter, it then begins to expand after the manner of a fan into fila- 
ments. These filaments or fasciculi penetrate the cineritious matter 
in various directions, besides those just detailed. A particular ex- 
position of them is given by Gall and Spurzheim, in their anatomy 
of the brain. 

The Tsenia Striata is placed in the angle formed between the 
internal margin of the Corpus Striatum, and the external one of 
the Thalamus Opticus, where these two bodies are in contact and 
continuous with one another. It is a small medullary band, not a 
line in breadth, commencing near the anterior crus of the fornix, 
with which it is connected frequently by filaments ; and observing 
the curved course of the fissure in which it is placed, it goes to the 
posterior end of the corpus striatum, and even beyond it in most 
cases, by uniting itself to the top of the Cornu Ammonis. 

The Corpus Callosum:* — When the fissure between the hemi- 
spheres of the cerebrum is widely separated, or when the superior 
part of the hemisphere is cut away on a level with the bottom of the 
fissure, the Corpus Callosum, a medullary layer, as stated, is brought 
fully into view. This body unites the medullary mass of the two 
hemispheres, and is a large commissure. It occupies about two- 
fifths of the long diameter of the brain, being nearer to its anterior 
than to its posterior end, and is about eight lines broad ; increasing, 
however, somewhat in breadth posteriorly. The lateral half of it, 
on either side, is concealed by the hemisphere overlapping it, but is, 

* Anat. Atlas, Fig. 535. 
34* 



394 NERVOUS SYSTEM. 

prevented from adhering by a horizontal fissure, which extends from 
one end to the other. It has an arched form, being convex above 
and concave below. Its thickness is uniformly about three lines, 
with the exception of its anterior and its posterior margin, which 
are more. Just above the horizontal fissure there exists a longitu- 
dinal layer of white neurine running from one end to the other of the 
fiat surface of the hemisphere, described by Mr. Solly.* 

The middle line of its upper surface is marked out from one end 
to the other by a very slight depression, the Raphe; on each side of 
which there is a very small linear elevation of the same extent, but 
slightly curved inwards towards its fellow. From these longitudinal 
lines there proceed outwardly transverse ones, having a filamentous 
appearance. At the anterior and posterior ends of the corpus callo- 
sum, the fibres are somewhat curved and radiate towards the peri- 
phery of the brain. Other longitudinal lines also exist on the surface 
of the corpus callosum, but they are not seen with equal facility. 
The anterior extremity of the corpus callosum is rounded off, and 
bent downwards towards the basis of the brain, in such a manner as 
to present backwards its concavity ; which thus embraces the fore 
part of the corpora striata, and closes the lateral ventricles at this 
point. The posterior end of the corpus callosum is rounded also, 
and continuous with the fornix and with the cornu ammonis. 

By examining the Corpus Callosum from below, or by looking at 
its relative situation and shape on a hemisphere which is accurately 
separated from its fellow in the middle line, it will be seen that its 
lower surface is very concave, being highly arched from before back- 
wards ; that it forms the roof of the lateral ventricles, and that this 
surface of it is about two inches in its transverse diameter, and, 
therefore, more than twice as broad as the upper surface. 

The Fornix,! {Trigone Cerebral, of the French) is placed imme- 
diately below the corpus callosum. It is a triangular body of 
medullary neurine or matter, the base of which is behind and the 
apex in front. It is about an inch and a half long in its body, and 
one inch wide at its base. It is the latter part, which, lying imme- 
diately beneath the posterior end of the corpus callosum, is con- 
tinuous with it, and causes the fornix to be considered as a part of 
the same structure with the corpus callosum. These two bodies, 

* Anatomy of Brain, 1836. + Anat. Atlas, Fig. 543. 



THE CEREBRUM. 395 

which may be compared to a sheet of medullary matter doubled on 
itself, have their surfaces in contact for a short distance behind, the 
fornix afterwards, by advancing and keeping itself in close contact 
with the thalami nervorum opticorum, which are just below it, di- 
verges more and more from the under surface of the corpus callosum. 
It conceals the upper surface of the thalami except their external 
margins, and, having reached their anterior extremities, its apex 
descends towards the basis of the brain. 

The body of the fornix is about a line thick, but at its anterior ex- 
tremity, it becomes somewhat cylindrical, and is divided into two 
columns or legs, called Crura Fornicis Anteriora. Each of these 
crura, in descending adheres to the anterior extremity of the tha- 
lamus of that side, and, getting finally below it into the floor of the 
third ventricle, it, after a course slightly curved, joins the cortical 
substance of the Eminentia Mammillaris. Santorini, aware of this 
junction, considered the eminentia? as a part of the fornix, and, 
therefore, called them Bulbi Fornicis. 

The fornix has other attachments of a more complex description, 
which the anatomist should attend to, as they serve to indicate the 
modes of intercourse between the several parts of the cerebrum. Its 
fibres having reached, and probably formed, the eminentia mammil- 
laris, one fasciculus of them ascends from thence along the internal 
face of the optic thalamus, invested by the cineritious matter of the 
latter, and spreads itself above like a fan, and forms the tuberculum 
anterius : a second fasciculus from the same point, having divided 
into two, after going a short distance, sends one division backwards 
along the upper internal face of the optic thalamus, to join the pe- 
duncle of the pineal gland, and the other division, which is more 
anterior, runs to join the taenia striata ; the third fasciculus from the 
eminentia mammillaris, being covered by the optic nerve, goes out- 
wards and backwards to terminate in the thalamus. 

The posterior margin, or the base of the fornix, besides running 
into the corpus callosum, has the angle on each side elongated so 
as to rest upon and to join the upper end of the cornu ammonis. 
The angle, being continued, then follows the winding course of the 
latter, adhering to its posterior margin, but hanging loosely over 
the anterior. This loose edge or continuation of the external mar- 
gin of the fornix is the Taenia Hippocampi, or Corpus Fimbriatum 
of the Lateral Ventricle. The elongations of the posterior angles are 
called Crura Posteriora Fornicis. In the brains of individuals who 



NERVOUS SYSTEM. 

have suffered from general dropsy, one frequently finds the fornix 
narrower than usual, and in its middle a fissure which separates 
almost completely its two halves. 

As the fornix is fitted to the upper surface of the optic thalami, 
it is of course concave below and convex above, or resembles a 
triangular arch resting upon its three points or angles. Owing to 
some misunderstanding of the original Greek word ^*/u<Jf ? , which, 
according to the interpretation of Sabatier, means a vault, and there- 
by expresses the whole body, anatomists, with the exception of him 
have generally supposed the striated under surface of the fornix to 
be meant by it, and have therefore called the surface Lyra, in which, 
mistake one has followed another. 

The Septum Lucidum is a partition placed vertically in the mid- 
dle line of the brain, and extends from the corpus callosum above 
to the fornix below. It is of a triangular shape, but irregularly so, 
being much broader before than it is behind, and having its edges 
so incurvated as to fit the bodies against which it is applied. 

The septum lucidum is formed by two laminae placed side to side, 
but not adhering to each other, and leaving, therefore, an interval 
between them, called the Ventriculus Septi, or the fifth ventricle. 
Each of these laminae consists of two layers: the internal is medul- 
lary substance, continuous with that of the corpus callosum and of 
the fornix ; and the external is a layer of cineritious substance. The 
cavity is about an inch and a half long by a line wide, and is nar- 
rower in the middle than at either extremity. It is lined by a de- 
licate serous membrane, which becomes manifest when the halitus 
that naturally covers its surface is accumulated into a body of water. 
It is generally supposed to be insulated or completely shut up, yet 
occasionally it has been found elongated in front, towards the space 
between the anterior commissure and the crura fornicis, and to com- 
municate there with the third ventricle.* 

The Pineal Gland (Glandula Pinealis, Conarium) is placed be- 
neath the posterior margin of the fornix, upon the superior of the 
tubercula quadrigemina, or the nates. It is an oblong conoidal 
body, the longest diameter of which is transverse, and amounts to 
three or four lines, while the short diameter is near three lines. 

* J. F. Meckel. 



THE CEREBRUM. 397 

These diameters are, however, sometimes reversed. The substance 
of the pineal gland is cineritious and of a reddish colour. At its 
inferior part there is a small cavity, sometimes lined with medullary 
matter, and the orifice of which looks towards the third ventricle. 

This body is connected to the adjacent parts by several cords. 
From its bottom there proceeds, on each side, the long medullary 
filament, called its peduncle, which runs along the upper internal 
face of the thalamus opticus, and, as observed, joins, or is conti- 
nuous with, one of the filamentous processes from the Eminentia 
Mammillaris as connected with the anterior cms of the fornix. 
From its base there proceeds a transverse lamina of medullary mat- 
ter, called the Posterior Commissure of the brain, which first ad- 
vances forwards, and then recedes, so as to be in some measure 
doubled on itself. This lamina, at either end, is united to the up- 
per posterior part of the corresponding optic thalamus, and by its 
lower margin runs into the superior edge of the tubercula quadri- 
gemina. 

Frequently, within the pineal gland, and sometimes on its sur- 
face, there is an accumulation of calcarious matter, the Acervulus 
Cerebri, that appears about the sixth year of life, and continues for 
ever afterwards. It is variable both in quantity and in its mode of 
concretion, for sometimes there are only a few atoms of grit, scarcely 
distinguishable by the feel ; while, on other occasions, it is collected 
into a body of irregular shape, and more than a line in diameter. 
The pieces of which the acervulus consists are sometimes united by 
cellular substance and enclosed in a sac. The chemical analysis 
presents phosphate of lime in large proportion, carbonate of lime, 
and animal matter. 

There are some analogies of texture between the exterior of the 
Pineal Gland and the Glandulse Pacchioni, as the latter appear on 
the different processes of pia mater. This analogy is closer than 
that of Pacchioni's glands in the longitudinal sinus, with those on 
the pia mater. 

A reflection of pia mater, called Velum Interpositum, separates 
the pineal gland from the fornix, and the fornix from the thalami 
nervorum opticorum. 



398 NERVOUS SYSTEM. 



Of the Ventricles of the Brain* 

These cavities are four in number: two, called lateral, are placed 
each one in its 'respective hemisphere of the cerebrum, a third is be- 
tween the two thalami, and the fourth under the cerebellum. They 
have all been alluded to, but only incidentally. 

The two Lateral Ventricles ( Ventriculi Laterales) are horizontal 
cavities, or fissures, of an extremely irregular shape, in the very 
centre of the" hemispheres, being the interval between the diverging 
and converging filaments of the cerebrum. They are separated from 
each other only by the septum lucidum ; are covered over by the 
corpus callosum, and have the fornix, thalami optici, and corpora 
striata for a floor. Each one consists in a body or principal cavity, 
and three processes, called cornua. The body has been sufficiently 
described in speaking of the parts which constitute its parietes ; but 
the processes are yet to be considered. 

The Cornua, from their position, are named Anterior, Posterior, 
and Lateral or Inferior. The Anterior is a very small space be- 
tween the anterior extremity of the corpus striatum and the opposite 
surface of the hemisphere, and has nothing in it particularly deserv- 
ing of notice. The Posterior Cornu extends from the base of the 
fornix to the distance of an inch or more in the substance of the 
posterior lobe of the cerebrum. Its cavity is conoidal, somewhat 
curved, with its convexity outwards, and is six or seven lines in 
diameter at its base. Its internal side is furnished with an oblong 
eminence called Hippocampus Minor, or Ergot, from its resemblance 
to a cock's spur, but its size and form are somewhat variable. When 
this eminence is cut through transversely, it is easy to see that it is 
formed by a convolution of the posterior lobe projecting into the pos- 
terior cornu. The convolution is covered by medullary matter on 
the side of the ventricle, and of course by cineritious on the side of 
the periphery of the brain, and is the bottom of an anfractuosity. 

The Inferior, Middle, or Lateral Cornu, of the Lateral ventricle 
is situated in the middle lobe of the cerebrum. It commences at 
the posterior angle of the fornix, and winds downwards and for- 
wards in a semicircle towards the fissure of Sylvius, presenting its 

* Anat. Atlas, Figs. 541 to 546, inclusive. 



VENTRICLES OF CEREBRUM. 399 

convexity outwards, and its concavity within. Its floor is furnished 
in its whole length with an elevated ridge, the surface of which is 
semi-cylindrical. This ridge is the Cornu Ammonis, or Hippocampus 
Major, and increases somewhat, both in breadth and elevation, as it 
w r inds down the process of the ventricle. Its lower or anterior ex- 
tremity is terminated by two or three small tubercles, and is the Pes 
Hippocampi. Occasionally the Hippocampus Major is marked ofT 
by a middle longitudinal fissure into two elevations, of which the 
external is the smaller. On its concave side there is the thin edge 
of medullary matter, continuous with the external margin of the fornix. 
The extremity of a knife handle may be insinuated for a short dis- 
tance between this edge and the Hippocampus; it ceases about half 
way down the latter, and in the natural state of the parts is concealed 
by the plexus choroides. This edge is, as mentioned in the account 
of the fornix, the Taenia Hippocampi or Corpus Fimbriatum of the 
lateral ventricle. Beneath the latter, and partially covered by it, 
there is another body, which presents itself in the form of a small 
cord of cineritious matter, not quite so long as the Taenia, and is 
called Fascia Dentata, from being divided into several sections by 
transverse fissures, which give it a tooth-like appearance. 

A transverse incision of the Hippocampus Major shows that it is 
a body of cineritious matter, covered on its surface by a thin layer 
of medullary substance. 

When the fornix is separated from its anterior crura and turned 
over backwards, the process of pia mater, called Velum Interposi- 
tum, is found between it and the optic thalami. This process is 
of a triangular shape, resembling the fornix, and is about the same 
size; it is insinuated into its place from the surface of the brain, 
under the posterior margin of the corpus callosum. Its lateral mar- 
gins, which project beyond the corresponding ones of the fornix, are 
formed by a congeries of convoluted vessels, constituting the 
Plexus Choroides. 

The Plexus Choroides, may be traced from the Pes Hippocampi 
along the corpus fimbriatum to its position on the margin of the 
velum interpositum ; and insinuates itself from the bottom of the 
cerebrum between the pons varolii and the convolution forming the 
Hippocampus Major ; but when it reaches the anterior end of the 
fornix its convoluted character ceases, and it terminates, on each 
side, in a single vein, ( Vena Galeni), which runs from before back- 



400 NERVOUS SYSTEM. 

wards, in a straight line, near the middle of the velum interpositum. 
The vein, finally, unites with its fellow to form a single trunk, which 
runs into the fourth sinus of the dura mater. 

This Velum Interpositum, called also Tela Choroidea, adheres 
very strongly to the fornix by means of small vessels : it may be 
raised with less difficulty from the thalami, though it serves to keep 
the third ventricle closed above, with the exception of the part just 
behind the crura of the fornix, where the third and the lateral ven- 
tricle communicate by the foramen of Monro. The pineal gland is 
entangled in its posterior part, being placed below it, and is generally 
torn from its peduncles when the tela is raised up. It is at this 
point that the tunica arachnoidea may be traced into the cavity of 
the lateral ventricles, according to Bichat.* 

The Plexus Choroides, which was stated to bound the Velum 
Interpositum on each side, and to descend along the Hippocampus 
Major to the fissure of Sylvius, or rather to ascend from this point, 
and to terminate in the vein on the side of the middle line of the 
Velum, is narrow at its termination, but increases continually in 
breadth as it is traced towards its commencement. The middle 
part, however, where it makes its turn, is an exception to this rule, 
for there it is larger in every way than elsewhere : its vessels being 
more capacious and more tortuous. Precisely at this point one or 
more vesicles are very frequently found, considered by some as hyda- 
tids of the brain ; in some cases they are filled with calcarious 
matter instead of with water. The Glandulae Pacchioni, as stated, 
also prevail at this margin. 

On the under surface of the Velum Interpositum, adhering to it, 
there is on each side a small venous plexus which goes from before 
backwards, and terminates in the vena galeni, near its junction with 
its fellow. It receives the blood of the third ventricle. 

There is also the same sort of plexus in the fourth ventricle. 

Upon the removal of the Velum Interpositum, or its elevation, 
the whole upper surface of the thalami optici is exposed. The third 
ventricle is also brought into view, being placed immediately between 
the thalami optici. 

* Some doubts, I have mentioned before, may be reasonably raised on this point of 
anatomy, as the evidence is seldom or never satisfactory to the full extent, and as 
such an arrangement would be contradictory to that of the tunica arachnoidea on the 
surface of the brain, which never dips into fissures. 



VENTRICLES OF CEREBRUM. 401 

The Third Ventricle, ( Ventriculus Tertius,) is a narrow oblong 
cavity, bounded below by the pons Tarini, crura cerebri and the 
eminentiae mammillares; and above by the velum interpositum and 
the fornix. It is an extension of the posterior middle fissure of the 
medulla oblongata conducted along the middle of the pons varolii. 
The anterior crura of the fornix are at its fore part, and just before 
them is the Anterior Commissure (Commissura Anterior.) This 
body is a transverse fasciculus of medullary matter, which passes 
from one hemisphere to the other through the anterior margins of 
the thalami optici. Its middle part is rounded and free, but its ex- 
tremity penetrates on each side into the substance of the anterior in- 
ferior portion of the corpus striatum, and spreading out gradually 
describes a curve with its convexity forwards, which terminates near 
the Pes Hippocampi of the inferior cornu of the lateral ventricle. 
This fasciculus, in penetrating the corpus striatum, does not mix 
with its substance, but, in the early part of its course, goes in a canal 
formed in the latter. In order to see this arrangement, a part of the 
corpus striatum must be removed. The anterior commissure resem- 
bles a nerve in its structure, as it is surrounded by a very delicate 
sheath, and is divided into fasciculi of fibres. It will now be under- 
stood that three commissures are found in the third ventricle, the 
Anterior Commissure — -the Posterior which is just in front of the 
Pineal Gland,* and the Soft Commissure, being a cineritious adhe- 
sion of the Thalami at their middle. f 

Just behind and below the anterior commissure, the base of the 
infundibulum opens into the third ventricle ; this place is the Iter ad 
Infundibulum. At the posterior extremity of the third ventricle, just 
below the posterior commissure, which has been described as a pro- 
cess of the pineal gland, the communication exists with the fourth 
ventricle. This passage is the Aqueduct of Sylvius, and leads ob- 
liquely downwards and backwards under the valve of the brain. 

The third ventricle communicates freely with the lateral ventricle 
dirough the aperture called the Foramen of Monro, which is situated 
precisely at the place where the plexus choroides terminates ; that is 
under the anterior cms of the fornix. Doubts have, from time to 
time, been suggested in regard to the natural existence of this com- 
munication; it only requires a moderate degree of accurate observa- 
tion to dispel them : they have arisen, probably, from the aperture 

* See Pineal Gland. + See Thalami. 

Vol. II.— 35 



402 NERVOUS SYSTEM. 

being shut up by the occasional adhesion of the plexus choroides to 
the contiguous surface of the brain. 

The Fourth Ventricle (Ventriculus Quartus, Cerebelli) has been, 
in a great degree, described in the account of the neighbouring parts; 
it will, therefore, be very readily understood on the present occasion. 
It is an irregular triangular cavity, the base of which is downwards. 
It is bounded in front by the tuber annulare, and the medulla ob- 
longata, behind by the fundamental portion of the cerebellum, and 
above by the valve of the brain and the tubercula quadrigemina; it 
is under the latter that the communication between it and the third 
ventricle is found. Its lateral parietes are formed by the medullary 
prolongations from the cerebellum to the tubercula quadrigemina. 
This cavity, as stated, is open below, when that portion of pia mater 
is removed, which passes from the cerebellum to the medulla ob- 
longata. 

From what has now been said of the connexion of the pia mater 
with the ventricles, it will be understood that as their surfaces are 
covered by pia mater, and the removal of it exposes their cavities, 
they are in fact, continuations of the external surface of the brain. 
The ventricles are generally found upon death to contain two or 
three tea-spoonsful of light coloured serum, called by Magendie the 
encephalo spinal fluid. In Williams, examined immediately after 
his execution, August 9, 1839, the encephalo spinal fluid, amount- 
ing to from two to three drachms, came out clear and abundant from 
the fourth ventricle ; on cutting through the tunica arachnoidea which 
bounds it below. 



SECT. VI. — OF THE NERVES OF THE ENCEPHALON.* 

These nervesf are designated numerically, from before backwards, 
and also, by some peculiarity of distribution of function. This nu- 

* The more improved observations of modern anatomists having pointed out the 
fallacy of considering the brain as the source of the spinal marrow, instead of the 
reverse ; it follows, that the proper order of describing the nerves of the encephalon, 
is successively from the spinal marrow. I had adopted this plan, formerly, but cer- 
tain considerations of facility in study, have induced me to abandon it after some 
years of experience. 

t Anat. Atlas, Figs. 533, 547. 



NERVES OF THE ENCEPHALON. 



403 



merical arrangement is the most sanctioned by age and general ad- 
mission, it is not, however, so unexceptionable as to avoid all ob- 
jections to it ; improvements have therefore been suggested from 
various quarters, founded on particular anatomical or physiological 
considerations; but the improvements themselves are exposed to ob- 
jections as strong as the ancient nomenclature. For example, the 
innovators are not agreed in regard to the proper number of nerves, 
nor on those which should be considered distinct from each other. 
Some do not consider the olfactory as a nerve, but only a ganglion ; 
some consider the glosso pharyngeal and par vagum as but one nerve, 
while others speak of them as two. Some make but one nerve of 
the third and sixth, owing to their common distribution to the mus- 
cles of the eye. It is evidently expedient, under these circumstances, 
to escape a farrago of opinions, by adhering to the most received 
classification, at least, till the ground of change be better explored 
and more universally acknowledged. If there be any thing of in- 
calculable importance to the comfort of students and scientific men 
generally, it is uniformity of language, or rather conformity to a re- 
ceived standard of nomenclature. The only justifiable departure 
from this rule, is where something new has been actually discovered, 
a necessity of course then exists for giving a new name, as it would 
not do to take the appropriated one of any thing else. 

The Olfactory Nerve (First Pair, Nervus Olfactoriics, Par Primum,) 
is situated on the under surface of the anterior lobes of the brain, 
near the fissure that separates the hemispheres. It goes forwards 
from its root, and also converges gradually towards its fellow, so as 
to reach the cribriform plate of the ethmoid bone, through the per- 
forations of which it passes out. In its course, it is lodged in a 
small furrow of the cerebrum, by which pressure upon it is pre- 
vented. 

This nerve arises by three medullary fasciculi, or roots, from the 
basis of the brain at the corpus striatum, in the fissure of Sylvius, 
where the anterior and middle lobes join each other : these roots are 
from eight to twelve lines on the outer side of the infundibulum. 
The roots are placed, in regard to each other diverging ; one is with- 
in, another in the middle, and the third external. The external 
root is the longest, and arises from the extreme posterior margin of 
the anterior lobe by its last convolution ; being connected with the 
middle lobe, and also with the anterior commissure of the brain. It 



404 



NERVOUS SYSTEM. 



has a curved course from without inwards, the concavity of which 
is forwards, and the convexity backwards. The internal root is 
concealed by the chiasm of the optic nerves, and arises from the ad- 
jacent surface of the anterior lobe. The middle root comes from 
the posterior margin of the anterior lobe by the cribriform surface, 
which is between the other two roots. These origins emanating 
from the cortical substance, unite to form a single prismatic cord, 
which increases in size as it advances forwards, and consists of me- 
dullary and cineritious longitudinal fibres mixed together. 

The anterior extremity of the olfactory nerve is swollen out into 
what is called the bulb,* (Bulbus,) and sends from its under surface 
filaments, which, surrounding themselves with a tunic from the dura 
mater, penetrate into the nose, and spread themselves on the Schnei- 
derian membrane. In its whole length it is exceedingly soft and 
pulpy, till it gets out of the cranium. 

The Optic Nerve, (Second Pair, JYervus Opticus, Par Secundum) 
is about the same size with the trigeminus. It arises by a broad 
flattened root, one portion of which comes from the posterior end of 
the thalamus opticus, and another from the testis through the means 
of a medullary band that passes from the latter, towards the thalamus 
of the same side. From this point the optic nerve winds forwards 
under the crus cerebri, adhering to it and forming a connexion with 
the tuber cinereum, and then inclining inwards towards its fellow. 
Its adhesion to the crus is considered by many anatomists as another 
of its origins. 

The optic nerve, having reached the under anterior part of the 
third ventricle, adheres so closely to its fellow that the two seem 
fused together, in such a way that there is no line of separation be- 
tween them. This junction receives, above from the third ventricle, 
some medullary filaments, which Meckel feels authorized to con- 
sider as another origin. The junction presents the form of the letter 
X, and is called the chiasm or crossing of the optic nerves. The 
most distinguished anatomists, however, have laboured in vain to 
settle the question of the mode of junction ; some believing that 
there was only a lateral union, others that the nerve of one side 
crossed over to the other side, and others, again, that the decussa- 

* Many anatomists consider this as a ganglion, from its extreme development in 
the sheep, bullock, horse, &c, and, therefore, call it the Olfactory Ganglion* Ro- 
lando. Solly on the Brain, &c. 



NERVES OF THE ENCEPHALON. 405 

tion occurred only with some of the fibres, but not all. Observa- 
tions, in comparative anatomy, on blindness, and indeed on every 
conceived mode of elucidation, have been resorted to without pro- 
ducing a solution of the problem; but the discussion of their merits 
would require too much space for the present work.* 

The optic nerves as they approach their chiasm become more 
cylindrical, and, continuing so afterwards, penetrate into the orbits 
through the foramina optica. It is only in front of their junction 
that they are invested by a neurileme ; which, having considerable 
firmness, penetrates into their interior, and divides them into dis- 
tinct canals. 

The Nervus Motor Oculi, (Third Pair, Par Tertium,) arises 
from the internal face of the crus cerebri, about two lines in ad- 
vance of the anterior margin of the tuber annulare. Its roots come, 
in great part, from the cineritious matter which is found on the sur- 
face of the crus, and may be traced for some distance upwards and 
backwards along the parietes of the third ventricle. The nerves of the 
opposite sides are in contact for some distance by the internal faces 
of their roots, but do not adhere, f 

The nervus motor oculi proceeds from its origin towards the 
external margin of the cavernous sinus, and, penetrating into the 
orbit through the sphenoidal foramen, it is distributed to most of the 
muscles of the eye-ball. 

The Pathetic Nerve, (Fourth Pair, Nervus Patheticm, Par Cere- 
brate Quartum) is the smallest which comes from the encephalon, 
and is not larger than a sewing thread. It arises by two filaments, 
or roots, from the upper end of the valve of the brain, just below the 
testis. This origin is soft, and easily broken, from the want of a 
neurileme ; but the latter is soon afterwards furnished. 

* Mr. Mayo, of London, considers ths posterior part of the junction as formed of 
fibres, making a curve, the convexity of which is forwards ; it is said to be very 
distinct in the mole, which has no other optic nerve. My own examinations have re- 
sulted in exhibiting decussating fibres behind, a junction in front like the two sides 
of the printed letter U, and a common mass in the centre. 

t Mr. Solly considers this nerve to arise from the interior of the pons Varolii, and 
to be connected with the valve of Vieusscns by some fibres from the latter, going into, 
the crus cerebri. 

35* 



406 NERVOUS SYSTEM. 

The nervus patheticus appears on the base of the brain, between 
the cerebellum and the posterior lobes of the cerebrum, at the ex- 
ternal margin of the tuber annulare. It then goes for some distance 
along the margin of the tentorium till it comes near the posterior 
clinoid process : it then penetrates into a canal of the dura mater, 
and reaches the orbit of the eye through the sphenoidal foramen, to 
be distributed on the superior oblique muscle. 

The Nervus Trigeminus, (Fifth Pair, Par Quintum, also called 
Trifacial) is one of the largest among those that proceed from the 
basis of the brain, and emerges from the side of the pons varolii, 
just where it is continuous with the cms cerebelli. It is composed 
of three roots : an anterior, a posterior, and a middle ;* of which the 
latter is much the largest. 

The middle root is about a line and a half in breadth, and has a 
passage made for it by the very obvious splitting of the superficial 
fibres of the pons Varolii. It is composed of thirty or forty fasciculi, 
which are divisible into a hundred or more fibres. These fasciculi 
may be traced into the substance of the pons Varolii, but inter- 
sected by the transverse fibres of the latter, in the direction of the 
fourth ventricle. When they have come near the latter, they may 
be traced thence into the medulla oblongata, towards the fissure that 
exists between the corpus olivare and restiforme. It is at this point, 
that the greater number of the fibres arise ; some from the corpus 
olivare, and others from the fissure. 

The commencement of this root is pulpy and destitute of fila- 
ments, and is surrounded by grayish substance; but when it has ad- 
vanced into the pons, it is surrounded by a fine membrane, and 
is very evidently filamentous. There is a successive increase in 
its size, from its commencement till it is ready to emerge from the 
pons; when it becomes somewhat contracted, and immediately after- 
wards increases again considerably in size. It then enters a canal 
of the dura mater at the fore part of the petrous portion of the tem- 
poral bone, and just behind the cavernous sinus. This canal sets 
but loosely about it at first, but afterwards it adheres to the surface 
of the nerve. 

The middle root of the nervus trigeminus, in the upper part of 

* Santorini, Observ. Anat. Venitia, ] 724. Soemmering, de Corp. Hum. Fabrica 
tiom. iv. Gall and Spurzheim, Anat. du Cerv. 



NERVES OF THE ENCEPHALON. 407 

the canal of the dura mater, preserves its fasciculated appearance, 
and many small filaments are interchanged between the fasciculi, 
so as to make a complex net-work. But, at the lower part of this 
canal, it is converted into a ganglion of a semi-lunar shape, with 
its concavity upwards, being about six or eight lines in length, and 
one and a half in breadth. This body called the Ganglion of 
Gasser, (Ganglion Semi-lunare, Plexus Gangliformis,) is compact, 
and has its fibres very much matted above, but below they assem- 
ble into larger and more distinct fasciculi, which are afterwards 
arranged into three principal trunks, departing from the cranium 
through different foramina ; to wit : through the sphenoidal foramen, 
the foramen rotundum, and the foramen ovale. 

J. F. Meckel asserts that the filaments of the plexus above the 
ganglion, for the most part terminate in a gutter formed in the su- 
perior margin of the ganglion, and that there are but very few of 
them which can be traced into the trunks below. The trunks be- 
low, consequently, arise from the circumference of the ganglion. 

The two smaller roots of the nervus trigeminus proceed out of 
the tuber annulare at different points, from that of the large root, 
and each one has its appropriate fissure for that purpose. One, 
from its situation, is, as stated, called Anterior, and the other Pos- 
terior. Each may be traced into the posterior cord of the medulla 
oblongata, but not so far as the large middle root, and is formed 
by several fasciculi of medullary fibres. The anterior and posterior 
root, after going separately for six or eight lines, unite to form a 
single cord.* This cord does not merge itself in the semi-lunar 
ganglion, but continues distinct from it,f with the exception of 
sending off to it a few fasciculi; and it sometimes has its own dis- 
tinct canal, and aperture in the dura mater, for passing through it ; 
it afterwards gets from the cranium through the foramen ovale, and 
is distributed to some of the'museles of mastication, as the temporal 
and the buccinator. 

The general distribution of the fifth pair of nerves, or the trige- 
minus, is to the orbit, to the face, and to the tongue. 

The Motor Externus Oculi, (Sixth Pair, Par Sextum), arises 

* These two constitute what is called the motory. part of the fifth nerve. Mr. 
Solly considers it to arise from the valve of the brain near its root. P. 249. 
t In this respect the fifth pair resembles one of the spinal nerves. 



408 NERVOUS SYSTEM. 

from the base or upper extremity of the corpus pyramidale, under 
the posterior margin of the tuber annulare or Pons: when the 
latter is broader than usual, some of the fibres seem to come from 
it ; but the appearance is deceptious, as they only penetrate it. The 
fibres are assembled into two roots, of which the internal is three 
or four times as large as the other. 

These roots before they penetrate the dura mater, most commonly 
unite into a single trunk, which goes almost directly forwards, and 
is enveloped in a neurileme. Passing through the cavernous sinus, 
it gets into the orbit by the sphenoidal foramen, and is spent upon 
the abductor oculi muscle. 

The Seventh Pair of Nerves is composed of the Facial and the 
Auditory. 

The Facial Nerve (Nervus Facialis, Portio Dura Septimi, Par 
Septimum) is placed in front of and above the auditory nerve. It 
arises by two branches, w T hich are perfectly distinct from each other, 
and differ much in their size. The larger one, which is placed 
within and above the other, arises from the medulla oblongata at the 
most superior part of the corpus restiforme, where the latter joins 
the tuber annulare. The origin of the nerve is sometimes over- 
lapped by the latter, so that some few of its fibres appear to come 
from the annular protuberance, while they only pass through it, in 
their course from the medulla oblongata. The second branch, 
which is much smaller than the other and is called by some the Pars 
Media of the Seventh Nerve, arises by three or four filaments, from 
that portion of the medulla oblongata which is placed between the 
first branch and the auditory nerve. 

The two branches of the facial nerve are kept distinct for the dis- 
tance of several lines before they unite. Proceeding outwards and 
backwards, they reach the meatus auditerius internus, and then pro- 
ceed, as a single cylindrical trunk, through the aqueduct of Fallopius 
to emerge at the stylo-mastoid foramen, for the purpose of being 
distributed upon the muscles and skin of the head. 

The Auditory Nerve (Nervus Auditorius, Jlcusticus , Portio Mollis 
Septimi) arises, in part, from the medullary striae on the surface of 
the calamus scriptorius, and partly from the corpus restiforme, be- 
tween the glosso-pharyngeal nerve and the tuber annulare. At its 
origin it is so extremely soft as not to bear handling, and is too 



NERVES OF THE ENCEPHALON. 409 

pulpy to present the appearance of fibres ; but, becoming more dis- 
tant from the medulla oblongata, it is harder and more fibrous. 

This nerve is impressed on its internal face by a longitudinal fur- 
row for the reception of the facial nerve. It passes obliquely for- 
wards and outwards beneath the crus cerebelli, and penetrates into 
the meatus auditorius internus. It adheres somewhat near its root 
to the under anterior margin of the cerebellum, just behind the crus 
of the latter: the circumstance is considered by J. F. Meckel, as a 
proof of its having there another origin, whereby an analogy is es- 
tablished between it and the two other nerves of the senses ; to wit, 
the optic and the olfactory. 

The distribution of this nerve is confined to the labyrinth of the 
ear. * 

The Eighth Pair of Nerves is composed of the Glosso-Pharyngeal, 
the Pneumogastric and the Spinal Accessory.* 

The Glosso-Pharyngeal Nerve (JYervus Glosso-Pharyngeus,) 
arises from the posterior cord of the medulla oblongata, just 
above, and somewhat anterior to the superior filaments of the 
next nerve, with which it is very closely connected. Its fila- 
ments, which are five or six in number, spring, therefore, from the 
anterior margin of the corpus restiforme, or from the fissure sepa- 
rating it from the corpus olivare,f under the posterior margin of the 
tuber annulare. 

Its filaments soon collect into a round cord, and anastomose, 
even in the cavity of the cranium, by a considerable branch with 
the pneumogastric. It runs outwards and backwards to the foramen 
lacerum posterius, and goes through the same division of it that the 
pneumogastric does, but in its own canal of the dura mater. About 
half an inch from this canal it enlarges within the cranium, into a 
small oblong ganglion of five or six lines long, which extends itself 
as far as the foramen lacerum.| 

Its general distribution is to the tongue and to the pharynx, as 

its name implies. 

* For an interesting 1 course of experiments on the eighth pair, by John Reid, 
M. D., see Essays on Physiology, Phil., 1838, from the Edinburgh Med. and Surgical 
Journal. 

t The Corpus Olivare is considered by Mr. Solly as its origin. 

X This ganglion is described by Andersech and by Huber, but its existence is 
questioned by Bichat. 



410 



NERVOUS SYSTEM. 



The Pneuniogastric Nerve (JVervus Pneumogastricus or Vagus) 
arises from the corpus restiforme of the medulla oblongata, just 
behind, or on the borders of the fissure separating it from the 
corpus olivare, somewhat above, and posterior to the highest 
root of the accessory nerve. It commences by a number of pa- 
rallel filaments, varying in number from ten to fifteen, which are 
placed very near each other, so as to form two or three flattened 
fasciculi of half an inch or more in length. The fasciculi below ad- 
here to the spinal accessory, and those above to the glossopharyn- 
geal nerve. The fasciculi, finally, collect into a single flattened cord 
of one and a half lines in breadth. 

This cord goes outwards and backwards to the foramen lacerum 
posterius, and gets through it in front of the internal jugular vein, 
being separated from the latter by the small spine which arises 
from the pars petrosa of the temporal bone. It passes through its 
own canal in the dura mater, being thus kept distinct from the 
glosso-pharyngeal, and from the accessory nerve, and in this canal 
the fasciculi which form it are collected into a single cylindrical 
trunk. After getting through the canal it then adheres, by a close, 
strong, cellular substance, to the glosso-pharyngeal and to the ac- 
cessory. 

The general plan of distribution of the pneumogastric nerve is, 
as its name implies, to the organs of respiration, and to the sto- 
mach. 

The Accessory Nerve, {JVervus Jlccessorius,) arises from the 
posterior fasciculus of the medulla oblongata, behind the nervus 
hypoglossus, and also from the posterior fasciculus of the me- 
dulla spinalis, sometimes as low down as the seventh cervical 
nerve. There are six or seven roots from the medulla spinalis, and 
about three or four from the medulla oblongata : the former are sin- 
gle, and run successively into the same trunk ; but the latter are 
each composed of two branches, consisting respectively of two or 
more filaments. These roots are, successively larger and longer, 
as they ascend to join the common trunk. The latter goes up be- 
tween the posterior fasciculi of spinal nerves and the ligamentum 
denticulatum, and gets into the cavity of the cranium, behind the 
vertebral artery, through the foramen magnum occipitis. It is joined 
sometimes by a sort of knot to the posterior fasciculi, or root of the 
first and second cervical nerves ; this knot seems to be neither after 



ARTERIES OF THE BRAIN. 411 

the fashion of ganglion or plexus, but is peculiar, and looks some- 
what as if one nerve were wrapped around the other. 

This nerve varies in respect to the number of its roots, and the 
mode of their origin. In all cases, the trunk, thus formed, passes 
from the cranium through the foramen lacerum posterius, traversing 
there the dura mater, either in a sheath common to it and to the 
pneumo-gastric nerve, or in its own particular opening behind that 
of the latter. 

Its general .distribution is to the muscles and to the integuments 
of the neck. 

The Hypoglossal Nerve, (Ninth Pair, (Nervus Hypoglossus,) 
arises from the medulla oblongata, by several fasciculi placed one 
above the other. The roots of these fasciculi spring from the fissure 
which separates the corpus pyramidale from the corpus olivare, 
being traced to that surface of the corpus pyramidale. The fasciculi 
are from four to eight in number, being subject to vary in different 
individuals. They unite into two or three trunks, which coalesce 
into one, after penetrating the dura mater by distinct openings ; and 
then proceed through the anterior condyloid foramen of the occipital 
bone. 

Santorini has observed in some cases a posterior root to the Hy- 
poglossal nerve, and in one instance where the same was found by 
Mayer it had a ganglion. 

The general distribution of this nerve is to the muscles of the 
tongue. 



'SECT. VII. OF THE ARTERIES OF THE BRAIN.* 

The arteries of the brain, or pia mater, are derived from the two 
internal carotids, and from the two vertebrals. 

The Internal Carotid Artery (Carotis Interna) gets into the cavity 
of the cranium through the carotid canal of the temporal bone, con- 
forming itself of course to the curvature of this canal, and is brought 
by it to the posterior part of the body of the sphenoidal bone. In 

* Anat. Atlas; Fig. 548. 



412 NERVOUS SYSTEM. 

escaping from the petrous bone it has to ascend, and also to advance 
somewhat, by which it is brought to the posterior part of the sella 
turcica. From this point it goes horizontally forwards through the 
cavernous sinus; and, reaching its fore part, it then ascends again, 
and towards the fissure of Sylvius. While in the carotid canal, it 
gives a small branch to the tympanum of the ear, and as it lies on 
the side of the sella turcica it gives off the anterior and the posterior 
artery of the cavernous sinus. When it reaches the anterior clinoid 
process it sends off a large branch, through the optic foramen, to the 
parts contained within the orbit of the eye. This branch is the oph- 
thalmic artery, and what remains of the internal cartoid is then dis- 
tributed to the brain after the following order: 

There are, first of all, some small branches sent to the adjacent 
parts ; as the pituitary gland, the infundibulum, and the lower part 
of the third ventricle. 

The Arteria Communicans Posterior is directed backwards and 
inwards, and runs into the adjacent branch of the basilar artery, 
called the posterior cerebral. There are some varieties in regard to 
the size and precise point of origin of the communicans posterior 
which it would be needless to mention particularly. Besides this 
important anastomosis, the internal carotid detaches several ramus- 
cles to the adjacent parts of the pia mater. 

The Arteria Choroidea is the next branch from the internal carotid. 
It goes outwards and backwards, and after detaching some minor 
branches, it penetrates into the inferior cornu of the lateral ventricle, 
by the side of the Pons Varolii, and expends itself in ramifications 
upon the plexus choroides. 

The Arteria Callosa, or Anterior Cerebri, is detached from the 
internal carotid, opposite the last. It advances in front of the union 
of the optic nerves, converging rapidly at the same time towards its 
fellow. Just before the chiasm of the optic nerves, a transverse 
branch passes between it and its fellow. This branch, the Arteria 
Communicans Anterior, is of variable length and size in different 
subjects, being sometimes a line, and on other occasions three or 
four lines long. Sometimes there are two arteries, one before the 
other. 

The arteria callosa then keeps near its fellow on the under sur- 
face of the hemisphere, giving out small branches ; and having got 



ARTERIES OF THE BRAIN. 413 

on a line with the anterior margin of the corpus callosum, it ascends 
on the flat side of the hemisphere, and divides into anterior and into 
posterior twigs. The former supply the fore flat part of the hemi- 
sphere ; the latter, the corpus callosum and the adjacent surface of 
the brain. These several branches of the arteria anterior, reach as 
far as the upper convex surface of the brain, and there anastomose 
with other arteries. 

The Internal Carotid may now be considered to have lost its name, 
and the trunk is continued as Arteria Media Cerebri. It is directed 
outwards, and engages in the fissure of Sylvius; while there it de- 
taches a great number of branches to the adjoining surfaces of the 
anterior and of the middle lobe. Some of these branches are of 
considerable magnitude, and winding along the convolutions of the 
brain, they at length ascend to the upper surface of the hemisphere, 
and anastomose with the branches of the anterior and of the posterior 
cerebral artery. 

The Vertebral Artery (Arteria Vertebralis) is a branch of the sub- 
clavian. In order to reach the cavity of the cranium it has to tra- 
verse the foramina of the transverse processes of the six upper verte- 
brae of the neck. It ascends in a straight line till it reaches the 
second vertebra, but there, in order to pass through the transverse 
process, it takes a direction upwards and outwards. It then ascends 
vertically again till it has passed through the transverse process of 
the first vertebra. After which it takes a horizontal course, winding 
around the posterior face of the upper oblique process of the same 
vertebra, in a depression for the purpose ; and having reached the 
internal extremity of this process, it ascends upwards and inwards 
through the occipital foramen into the cavity of the cranium, perfora- 
ting the dura mater just above the condyle of the occipital bone. 
Having got into the cranium, it is first on the side and then on the 
under surface of the medulla oblongata, and continues to approach 
its fellow till it reaches the posterior margin of the tuber annulare. 
At this point the two vertebral arteries coalesce, and from their union 
results the basilar artery. 

The vertebral artery in this course, from its origin to its termi- 
nation, detaches several arterioles to the heads of the adjoining 
muscles, to the membranes of the spinal marrow, and to the nerves 
as they come out of the intervertebral foramina : they are generally 
too small and irregular to deserve a special description. At its 

Vol. II.— 36 



41-1 NERVOUS SYSTEM. 

upper extremity, however, it sends off three branches of some con- 
sequence : the Spinalis Posterior, the Spinalis Anterior,* and the 
Inferior Cerebelli. 

The Arteria Inferior Cerebelli divides shortly after its origin, or 
otherwise is double from the beginning. The most posterior trunk 
is distributed about the bottom of the fourth ventricle, on the fun- 
damental portion of the cerebellum, and the contiguous faces of 
the two hemispheres or lobes of the latter. The other trunk of this 
artery is distributed on the under surface of the cerebellum. 

The Basilar Artery {Jirteria Basilaris) is on the middle line of 
the tuber annulare, and extends from its posterior to its anterior 
margin. In this course it detaches some arterioles to the tuber ; 
others to the meatus auditorius internus, (Arterice Auditivce Interna;,) 
which are spent upon the labyrinth, and anastomose with twigs from 
the internal and external carotids. At its anterior extremity it de- 
taches on each side two considerable trunks ; first the superior artery 
of the cerebellum, and immediately afterwards the posterior artery 
of the cerebrum. 

The Arteria Superior Cerebelli goes outwardly from its origin just 
behind the anterior edge of the tuber annulare, until it gains the front 
margin of the cerebellum. It then divides into several branches, 
some of which are distributed on the upper surface of the cerebellum 
and run to its posterior margin, where they anastomose with the 
branches of the arteria inferior : others are spent upon the substance 
of the cerebellum near its anterior edge. 

The Posterior Artery of the Cerebrum, [Arteria Cerebri Posterior,) 
one on each side, is the termination of the basilar artery. It pro- 
ceeds abruptly outwards, and has gone but a few lines when it re- 
ceives the arteria communicans posterior of the internal carotid. It 
then continues outwardly parallel with the anterior margin of the 
tuber annulare, and near it crosses the crus cerebri, and is then dis- 
tributed, on the inferior and on the posterior part of the hemisphere 
and of the corpus callosum. As mentioned, its branches anastomose 
with those of the anterior and of the middle artery of the cerebrum. 

It will now be understood, that an arterial circle or link encloses 
the chiasm of the optic nerves and the corpora albicantia. The 

* Sec Arteries of Medulla Spinalis. 



ARTERIES OF THE BRAIN. 415 

fore and lateral parts of the circle are formed by the internal caro- 
tids and their branches ; while the hind part is formed by the Ba- 
silar Artery and its bifurcation. This is the circle of Willis, and 
establishes a very free communication between the vessels of the 
two sides of the brain. 



The veins of the Brain have been sufficiently alluded to in the 
account of the Pia Mater, and of the sinuses of the Dura Mater. 



BOOK IX. 

PART III, 

SENSES. 

To the peripheral portion of the nervous system, belong all the 
nerves which are sent off from the Medulla Spinalis and Encepha- 
lon, and also the Sympathetic. Some of these nerves have a special 
apparatus attached to their external extremities, for the purpose of 
augmenting and facilitating their appropriate powers of sensation ; of 
this class are the Olfactory, the Optic, and the Auditory. Others of 
them, as the nerves of the tongue and of the skin, though they are the 
means of special sensation, yet the apparatus upon which they are 
spread is applied to many purposes, more striking and useful, than 
that of indicating the presence of surrounding bodies. And, lastly, 
the remaining nerves, being by far the most numerous and large, are 
distributed to the muscles and to the viscera,. 



CHAPTER L 



Of the Organ of Smelling, or the Nose.* 

The senses of Vision and Hearing are so insulated in their offices, 
that there can be no doubt of the propriety of considering them as 
belonging to the peripheral portion of the nervous system : but the 
nose being in the human subject, though not in all animals, attached 

* Anat. Atlas, Fig3. 549 to 557, inclusive.. 
36* 



418 NERVOUS SYSTEM. 

to the function of respiration, its association here is less admissible. 
Without detailing the considerations which have induced me to put 
its description under this head, I will only mention that I have been 
principally actuated by its office of smelling and by its position. 

In common language, the term nose is applied to the part of the 
organ of smelling which manifests itself externally ; but a very ex- 
tensive cavity of the same vertical diameter, and divided into two 
equal compartments, exists behind it, the form of which has been 
described in the account of the bones of the nose. This cavity ex- 
tends from the bottom of the cranium to the roof of the mouth, and 
backwards to within an inch and a quarter of the vertebrae of the 
neck. The nose, externally, is generally pyramidal, and has its 
base below ; what is technically called the root of the nose is the 
part contiguous to the forehead. The base, on each side, is marked 
from the cheek by a semi-circular depression ; which becoming more 
and more shallow at its upper extremity, and increasing in breadth, 
is insensibly lost upon the side and point of the nose. The ala nasi 
is the swell of the posterior part of the base, being bounded behind 
by the above depression. The base of the nose offers on each side 
an oblong oval orifice, looking downwards and having its long dia- 
meter forwards and slightly inwards. These openings are com- 
monly about two lines below the floor of the nose, but there is a 
diversity in this respect. 

The Nasus Cartilagineus, or the cartilaginous portion of the nose 
is placed wholly at its anterior extremity, and serves to elongate the 
cavity in that direction. It presents a vertical cartilage, which is in 
continuation of the bony septum : on each side of this, there is an 
oval cartilage, and behind and below the latter, several distinct and 
small pieces of cartilage, which preserve the form of the alse nasi, 
and constitute their foundation. 

The Vertical Cartilage, or Cartilaginous Septum {Septum Carti- 
laginmm,) is placed on the middle line of the nose, and has its an- 
terior angle projecting beyond the bony orifice of the anterior nares. 
Occasionally from a faulty conformation, it inclines more to one 
side than to the other. It adheres by its superior margin, to the 
nasal lamella of the ethmoid and to the middle nasal suture, and be- 
hind to the anterior margin of the vomer. The inferior margin is 
free in the greater part of its extent, but adheres behind to the suture 
between the maxillary bones. The anterior margin sends out, on 



ORGAN OF SMELLING. 419 

each side, a triangular plate, the upper edge of which, adheres to the 
inferior margin of the nasal bone, and of the nasal process of the 
upper maxillary. These plates form the upper part of the cartilagi- 
nous nose, and from their ligamentous attachment to the bones, admit 
of a slight motion from side to side. 

Huschke has described* a distinct cartilage at each side of the 
cartilaginous septum below, which may be found separate by macera- 
tion, he calls them the Vomerian cartilages. They are about half an 
inch in length, and the point of the Vomer is insinuated between 
them. 

The Oval Cartilages, one on each side, are a sort of semi-elliptical 
ring, deficient or open at their posterior end. The external side of the 
ring, is an oblong oval plate, which is directed upwards and back- 
wards. The internal half of the ring is much narrower, and pro- 
ceeds backwards from the preceding part at a very acute angle : its 
superior margin is in contact with the septum cartilagineum ; its in- 
ferior margin reaches below the latter, and its anterior extremity is 
in contact with its fellow, owing to the cartilaginous septum not 
reaching so far forwards. The place of contact of the two oval car- 
tilages with each other, forms the tip of the nose and the Columna 
Nasi, and gives the apparent thickness, before dissection, to the 
lower part of the septum narium. 

The Alae Nasi, or the convexities on each side of the base of the 
nose, it has been said owe their shape to the presence of several 
small pieces of cartilage, whose form, size, and number are too 
variable to admit of a standard description : occasionally they are 
all collected into but one cartilage. They serve a similar purpose 
with the oval cartilage, and with it are the means by which the ori- 
fice of the nostril is kept patulous. They are deposited in, and 
held together by a ligamentous membrane. This membrane at- 
taches them to the lateral margin of the anterior bony naris, and 
also unites the upper edge of the external plate of the oval cartilage 
to the inferior margin of the triangular plate of the cartilaginous 
septum. It is the length and looseness of this ligament which per- 
mit such free motion to the end of the nose. In addition there ex- 
ists a small ligament described by Caldani, which goes from the 
posterior end of the columna nasi to the anterior inferior margin of 
the bony nares. 

* Loc. cit. p. 5»7. 



420 NERVOUS SYSTEM. 

The skin which covers the upper half of the nose is loosely at- 
tached, by cellular substance, to the subjacent parts, but it adheres 
very closely by fibrous filaments to the surface of the cartilaginous 
and ligamentous structure, and is abundantly furnished with seba- 
ceous follicles. The exterior orifices of the latter are apparent, and 
are often filled with their appropriate fluid in an inspissated state, 
and which, when forced out by pressure, assumes the form of small 
worms, the blackness of the end of which is only dirt. 

There are several muscles destined to move the cartilaginous 
structure of the nose, and which have been described among those 
belonging to the face. They are, 

The Levator Labii Superioris Alaeque Nasi which lies upon the 
side of the nose and coming from the superior part of the nasal pro- 
cess and body of the upper maxillary bone, is, besides its insertion 
into the upper lip, connected with the ala nasi, and will draw the 
latter upwards : — 

The Compressor Naris, which arising from the ala nasi by a small 
pointed beginning, is spread out upon the upper edge of the oval 
cartilage and upon the triangular plate of the cartilaginous septum, 
so as to cover them, and is inserted into its fellow on the middle 
line : — 

The Depressor Labii Superioris Alaeque Nasi, which by arising 
from the roots of the alveolar processes of the incisor and canine 
teeth of the upper jaw, and going to be inserted into the ala nasi, as 
well as into the upper lip, will draw the ala nasi downwards : — 

And the Nasalis Labii Superioris, or Depressor Narium, which 
being the pointed production from the orbicularis oris, goes into 
the columna nasi, and will draw the latter downwards and back- 
wards. 

The Mucous Membrane of the Nose (Membrana Pituitaria, 
Schneideriana) lines the whole of each side of the nose, penetrates 
into the several sinuses and cavities communicating with it, and is 
continuous, at the orifice of the Nostrils, with the skin, and at the 
posterior nares, with the mucous membrane of the pharynx. 

It is not of essential importance to trace its course from any par- 
ticular point, but for the sake of perspicuity, we may begin at the 
floor of the nostril which it covers in a smooth even manner, some- 
times leaving a small opening into the mouth, by the foramen inci- 
sivum. This opening is called the duct of Stenson, an anatomist 



ORGAN OF SMELLING. 421 

of the seventeenth century, who discovered it. From below it as- 
cends on the septum narium, which it covers also smoothly without 
forming any fold or duplicature, and adheres so loosely that it may 
be detached with great facility. Behind, it covers the body of the 
sphenoid bone, and lines its cell; in front, it covers smoothly the os 
nasi and nasal process of the upper maxillary bone, and also the car- 
tilaginous nose. Above, it is reflected upon the cribriform plate of 
the ethmoid bone, and blocks up all its foramina. At this point, 
the olfactory nerves seem to terminate on its surface and adhere very 
closely to it. 

From the cribriform plate, the Schneiderian membrane passes to 
the cellular part of the ethmoid, and covers smoothly its anterior 
half. But behind, as it passes over the upper spongy bone, a pen- 
dulous duplicature is formed along its inferior margin, and is con- 
tinued beyond the bone, backwards as far as the spheno-palatine 
foramen. It then lines the upper meatus and the posterior cells of 
the ethmoid, and is extended upon the convex surface of the middle 
spongy bone. At the inferior margin of the latter, it forms another 
loose and somewhat pendulous duplication, which does not go much 
beyond the posterior extremity of the bone. The membrane is then 
reflected into the middle meatus of the nose, and penetrates into the 
maxillary sinus which it lines completely. The orifice through which 
it enters, is about the size of a crow-quill ; is variable in its situation, 
being sometimes in the middle of the meatus, sometimes more for- 
ward, and on other occasions higher up and concealed by irregu- 
larities, in the conformation of the ethmoid. This orifice, which 
was found to be so large and jagged in the prepared bone, is re- 
duced to its present size entirely by the mode of reflection of the 
mucous membrane over its margins. In front of the latter orifice, 
beneath the anterior margin of the middle turbinated bone, the mu- 
cous membrane is reflected into the anterior ethmoidal cells by one 
or more foramina, and through the most anterior of these cells into 
the frontal sinus. 

From the middle meatus, this membrane passes upon the lower 
turbinated bone so as to cover it, and also to form a loose duplica- 
tion along its inferior margin ; it then lines the inferior meatus of the 
nose, and is continued on its floor into the part from which its de- 
scription commenced. Under the anterior part of the inferior spongy 
bone, this membrane is continued into the lining membrane of the 
lachrymal sac, and there forms a fold frequently resembling a valve. 



iC2 NERVOUS SYSTEM. 

Along the posterior margin of the vomer, the membrane of the nostril 
is continued into the corresponding one of the other side, whose ar- 
rangement is in all respects the same. 

The pituitary membrane, in its structure and appearance, resem- 
bles other mucous membranes ; its colour, however, is naturally of a 
deeper red. It consists of two lamina?, which cannot be readily 
separated : the one next to the cavity of the nostril has the mucous 
structure ; the exterior one is fibrous, and resembles the periosteum 
of other parts of the body. This composition is best seen on the 
part belonging to the septum narium. 

By floating the pituitary membrane in water its mucous lamina 
is made to exhibit, very satisfactorily, the villous and spongy ap- 
pearance. This is particularly evident on the turbinated bones. Its 
whole surface is studded with pits or follicles of various sizes, irre- 
gularly arranged and resembling pricks made into a plastic substance 
with the point of a pin. From these cavities or cryptae proceeds the 
mucus of the nose. In the thickness of the pituitary membrane, 
there exist numerous and thickly set glands, of a size so small that 
they escape common observation, but their existence is generally 
admitted, both on the authority of anatomists who have described 
them,* and on the principle of their being always the concomitants 
of mucous membranes.f 

These glands, according to Valentin, in some parts of the nose 
consist of contorted tubes, resembling somewhat microscopic intes- 
tines ; and which are surrounded and separated by circular filaments 
of cellular substance. The glands are especially well developed at 
the posterior and inferior part of the septum narium. 

It is owing to the great abundance of blood vessels in this mem- 
brane, to their very superficial course, and' to the habitual residence 
of blood in them, that it always presents a deep red colour in the 
living state. These blood vessels bleed very freely from slight me- 
chanical" causes, and are also disposed to congestions, which are 
relieved by the blood being poured out through their exhalant ori- 
fices, without laceration or any solution of continuity. 

Though the description just given corresponds with the texture, 
generally, of the pituitary membrane, yet there are modifications of 
the latter at particular points which it does not fully suit. For ex- 
ample, at the anterior orifice of the nostril it is insensibly changed" 

* Ruyschii, Epist. Anat. Probl. vii. Mayer. t Bichat, Anat. Dcscriju 



ORGAN OF SMELLING. 423 

into a thin skin, furnished in the male adult with stiff hairs ( Vibrissa ;) 
and in all the sinuses it is more thin and white than elsewhere, being 
also smooth and shining, and not presenting clearly the little pits 
which are so distinct in the nose. The surface which adheres to the 
sides of the sinuses, is destitute of a fibrous structure, and resembles 
condensed but very thin cellular membrane, and is so loosely attached 
that it peels off with a very inconsiderable force. When the mem- 
brane of the sinuses is inflamed, it then thickens, admits more red 
blood, and is thus brought to resemble the pituitary elsewhere. 

It is extremely difficult to assign a proper use to the sinuses bor- 
dering on and entering into the nose ; for, according to Dessault, the 
sensation of smell does not exist in them. Bichat believed that they, 
by being filled with air charged with odorous particles, were reser- 
voirs of the latter, serving to prolong the sensation of smell, which 
would have been too fugitive if it had depended only on the passage 
of air during respiration. Another problem in regard to these cavi- 
ties, is the manner in which they discharge the mucus which they 
secrete. Perfectly rigid and unyielding, and so situated that the 
most frequent attitudes of the head would rather serve to retain, than 
to discharge the contents of most of them by gravitation, we yet 
seldom see their surface more than smeared with mucus, and accu- 
mulations of it are quite uncommon, except in the diseased state. 
The secretion in them, it is to be observed, is much less abundant 
than it is in the nose. 



Of the Nerves of the Pituitary Xlembrane** 

The pituitary membrane is furnished with nervesf from two 
sources ; from the olfactory, and from the fifth pair. 

The Olfactory Nerve having formed its bulb, which reposes in 
the ethmoidal fossa, sends off from the under surface of the bulb, 
the succession of filaments which penetrate to the nose through the 
cribriform plate of the ethmoidal bone. The latter, when examined 
from the upper surface, has its foramina arranged into two rows, one 
next to the crista galli, and the other next to the cellular portion of 
the ethmoid. Each row consists of about six or eight foramina, and 
between these rows there are other foramina, smaller, and not so 

* Antonii Scarpa, Anatom. Annolationes, Lib. ii. 
t Anat. Atlas, Fig. GIG. 



424 NERVOUS SYSTEM. 

much in a line with each other. The same cribriform foramina, 
when examined from the cavity of the nose, are more numerous, es- 
pecially those belonging to the first two rows, in consequence of 
the latter branching out below into several canals, which may be seen 
very distinctly on the side of the base of the nasal lamella, and on 
that of the cellular portion of the ethmoid. 

The distribution of the olfactory nerve corresponds with this ar- 
rangement of the cribriform plate ; for it has three rows of branches 
proceeding from the under surface of its bulb, each branch going 
through its appropriate foramen, and subdividing in it ; but sometimes 
two filaments pass through the same foramen. In a short space after 
their origin, they become invested by sheaths of the dura mater, 
which are extended a considerable distance, and which, by a close 
adhesion to the nerves, make them appear much larger below than 
they are at the roots. "When the nerves reach the cavity of the nose 
they anastomose together, and descending between the bone and the 
pituitary membrane, they ramify into an infinitude of small branches, 
the terminating filaments of which reach the nasal surface of the 
membrane* 

The Internal Branches, or those next to the crista galli, diverge 
from the cribriform plate, and pass downward between the septum 
and the pituitary membrane : where they first appear in the nose, 
there are some few adhesions or anastomoses between them ; but 
their filaments afterwards keep perfectly distinct, and, spreading 
themselves out on the pituitary membrane of the septum, make an 
appearance resembling a flat camel's hair pencil. The middle ones 
are the longest, and may be traced almost to the floor of the nose ; 
the anterior are shorter somewhat ; the posterior do not reach ob- 
viously below the middle of the septum. 

The External Branches have a very different mode of distribu- 
tion. While still in their canals they divide into many filaments, 
which anastomose frequently with each other, and when they have 
fairly got into the cavity of the nose, the same frequency of anasto- 
mosis continues, so that they form a net-work of numerous and small 
meshes, which prevails from the cribriform plate to the inferior 
margin of the middle turbinated bone. Their filaments cannot be 
traced below the latter line, and therefore, do not descend so low as 
the filaments of the internal row, neither are they so close to each 
other. They do not penetrate to the ethmoidal cells. The posterior 
ones are very abundant, on the upper turbinated bone, and incline 



ORGAN OF SMELLING. 425 

backwards in their descent ; the anterior are also abundant on the 
flat anterior half of the ethmoid, and when they get below the line of 
the upper meatus, they extend backwards to the posterior end of the 
middle turbinated bone, and to its inferior margin. On this bone 
they are less abundant than above it ; their meshes are larger, and 
their distribution its confined to the Schneiderian membrane covering 
its convex surface. 

The filaments of the Middle row from the Bulb of the Olfactory 
nerve, associate themselves indiscriminately with those of the external 
and of the internal row, according to local convenience. 

The other nerves of the Pituitary Membrane come from the first, 
and from the second branch of the Trigeminus. The first branch 
of the latter gives off from its nasal branch the nerve called Internal 
Nasal, which penetrates from the orbit into the cavity of the cranium, 
through the anterior internal orbitary foramen, and lies covered by 
the dura mater, at the side of the crista galli ; thence it passes into 
the cavity of the nose through the most anterior foramen of the crib- 
riform plate. 

The Internal Nasal Nerve (Nasalis Interims) having got into the 
nose divides into two fasciculi, an internal and an external. The 
internal descends along the anterior margin of the septum, between 
the mucous membrane and the bone, and, after a short course, is 
divided into two filaments, one of which applying itself to the pos- 
terior face of the os nasi, terminates by smaller filaments in the in- 
teguments of the lower part of the nose ; the other filament continues 
along the margin of the septum to its lower part, where it terminates 
by smaller filaments. The external fasciculus of the Nasalis Inter- 
nus gives off early a filament, which descends along a groove on 
the posterior face of the nasal bone, and winding over the lower 
edge of the latter, or passing through a foramen in it, is lost upon 
the integuments of the corresponding part of the nose. Other fila- 
ments from the external fasciculus descend upon the mucous mem- 
brane, along the external anterior part of the nose or that which 
corresponds with the nasal process of the upper maxilla, and termi- 
nate near the anterior extremity of the inferior spongy bone : they are 
three or four in number. The internal nasal nerve is also said to 
send one or more filaments to the frontal sinus, but they are so fine 
that doubts of their existence are entertained by Bichat, though 
they are admitted by J. F. MeckeL 

Vol. II.— 37 



426 NERVOUS SYSTEM. 

The Sphenopalatine Ganglion, a part of the second branch of 
the Trigeminus, detaches to the nose, through the sphenopalatine 
foramen, several filaments. One of these discovered by Cotun- 
nius, and admirably delineated by Scarpa and by John Hunter, 
called the Naso-Palatinus, runs across the front of the sphenoidal 
sinus to the upper posterior part of the septum narium, beneath the 
mucous membrane. It then descends obliquely along the septum 
to the foramen incisivum, and passes through it to the root of the 
mouth. In many cases, however, a distinct foramen is formed in 
the middle palate suture for it, anterior to the foramen incisivum. 
The nerve of the left side is anterior to that on the right. When 
the two reach the roof of the mouth, or are near it, they unite to 
form a little swelling called the naso-palatine ganglion,* from 
which several filaments arise, and are spent upon the membranous 
caruncle at this point, and upon the contiguous part of the palatine 
membrane. 

The spheno-palatine ganglion sends several filaments to the mu- 
cous membrane of the upper spongy-bone and of the upper meatus, 
and to that of the posterior end of the middle spongy bone. The 
palatine nerve, one of its largest branches, in descending along the 
posterior palatine canal to the soft palate of the mouth, also contri- 
butes to the supply of nerves to the nose. Shortly after it has arisen 
from the ganglion, it sends one or more filaments to the middle 
spongy bone, and to the superior part of the lower spongy bone, and 
when it has got, in its descent, on a level with the posterior end of 
the latter, it detaches another filament, which supplies the mucous 
membrane, along the inferior margin of this bone. 

In regard to the termination of these several orders of nerves, it is 
generally held that the filaments of the olfactory, end in brush-like ex- 
tremities. Klencke,f however, asserts that on the septum, they form 
distinctly cylindrical filaments, ending in fine loops, while elsewhere 
they end by a very delicate capillary net-work. Huschke,^ claims to 
have observed the arteries of the Schneiderian membrane attended by 
filaments of the sympathetic, and has advanced the opinion that the 
naso-palatine nerve is itself only the upper end of the great sympa- 
thetic. It is probable that the filaments of the fifth pair belonging 
to the nose, end as elsewhere by terminal loops. 

An opinion advanced by Mery about the close of the seventeenth 

* J, Cloquet, Anat. f Huschke, loc. cit. p. 565. t Loc. cit. 



THE EYE. 427 

century, has been revived by M. Magendie, of Paris, that the olfactory 
nerves are not those which communicate the impressions of odorous 
bodies. In contradiction, however, to his experiments, it should be 
stated, that several respectable anatomists have seen cases where 
the privation of the sense of smell during life, was found, upon ex- 
amination after death, to be attended with the absence of the olfac- 
tory nerves. 



Of the Blood Vessels of the Nose. 

The extreme vascularity of the Schneiderian Membrane is derived 
from several sources. The Internal Maxillary Artery sends through 
the Spheno-Palatine Foramen a large branch, which is distributed 
upon the septum and upon the spongy bones : The superior palatine 
artery supplies this membrane with one or more small branches : 
The Ophthalmic also sends the anterior and the posterior ethmoidal 
branches to it, from the orbit of the eye. The Infra-orbitar artery 
likewise contributes to its vascularity by one or more branches, sent 
off in its course through the infra-orbitar canal. 

The veins follow the course and distribution of the arteries. Some 
of them, however, unite with the trunks called emissaries of Santo- 
rini, which come from the sinuses of the dura mater through the 
foramen ovale and rotundum of the sphenoid bone. They are ex- 
tremely superficial with very thin parietes, hence they bleed from 
the most trivial causes. 



CHAPTER II. 



Of the Eye, and its Dependencies. 

The organ of vision which depends upon the optic nerve for its 
usefulness, is formed by the Ball of the Eye and many Dependen- 
cies or Auxiliary parts, all of which are situated within the orbit, 
and fill up its cavity. 



428 NERVOUS SYSTEM. 



SECT. I. — OF THE AUXILIARY PARTS OF THE EYE.* 

The Eyelids (Palpebrce) are placed at the anterior orifice of the 
orbit, and serve to shut out the light from the eye, by their closing ; 
and also, by their frequent motions, to sweep the front of the eye- 
ball, so as to remove, from its transparent part, moats and dust. 
They are distinguished into upper and lower, and the place at each 
end, where the horizontal fissure between them ceases, is called their 
Commissure, Angle or Canthus. The angle next to the nose, or 
the internal, is called the Great one, and the other,the Little one. 

The Internal Canthus is united to the nasal process of the supe- 
rior maxillary bone by a rounded tendon, (Ligamentum Palpebrale 
Internum,) the origin of the orbicularis palpebrarum muscle ; and 
which passes horizontally inwards, being nearly half an inch in 
length. It throws the skin into a small ridge, which may be dis- 
tinctly seen and felt at this point. The External Canthus is held 
in place by its general attachments of cellular substance and by the 
external palpebral ligament. 

The upper eyelid is somewhat larger than the lower, but the 
structure of both is the same, for each one is formed by skin exter- 
nally ; next to it a plane of muscular fibres, being the orbicularis 
palpebrarum ; then a plate of cartilage ; and, lastly, a thin mem- 
brane uniting it to the eyeball. 

There is nothing in the texture of the skin of the eyelid which 
needs description in a manner more particular than that of stating 
its fineness, its thinness, the looseness of its attachment to the mus- 
cle beneath by long yielding cellular substance, and the deficiency 
of adipose matter. The skin is rendered prominent at the superior 
margin of the orbit, both by the projection of the bone there, and by 
the presence of the corrugator supercilii muscle at its internal extre- 
mity. This prominence is furnished with an arched cluster of hairs, 
(Supercilia,) which have their loose ends inclined horizontally out- 
wards, and are rather more abundant at the root of the nose than ex- 
ternally. The supercilia of the two sides are separated commonly 
by a small bare space called Glabella, the existence of which adds 
much to the calm and intellectual expression of the human counte- 

* Anat. Atlas, Figs. 558 to 564, inclusive. 



THE EYE. 429 

nance ; whereas, the junction of the two eyebrows, by the hairs 
filling up this space, gives a gloomy, and occasionally, a ferocious 
appearance. 

The margins of the eyelids are also furnished with hairs, (Cilia) 
the roots of which are insinuated between the skin and the tarsi car- 
tilages: the most deeply seated seem, indeed, to penetrate the latter. 
The hairs of the upper lid are longer and more numerous than those 
of the lower : they are concave upwards, while the latter are con- 
cave downwards, so that the convexities of the two ranges of hairs 
come in contact when the eyelids are closed. The hairs of each 
cilium are disposed into three or four rows, by which a long brush 
is formed, the central hairs of which are longer and larger than any 
others. 

The hairs of the supercilia and of the cilia resemble one another 
strongly, for, when examined closely, each one will be found to 
have a bulbous soft root, just beyond which there is a narrow part. 
The middle of the hair is swollen, and its external extremity is 
brought to a fine point. These hairs correspond in colour with the 
hairs of the head. 

When the orbicularis muscle is removed, a ligamentous or fibrous 
membrane is found passing from the external margin of the orbit to 
the corresponding margin of the palpebral cartilages, and separating 
the eyelids from the parts contained within the orbit. There is a 
partial decussation of the fibres of this membrane, from the external 
commissure of the cartilages to the adjoining edge of the orbit ; it 
has more firmness than any other part of the membrane, and is the 
external palpebral ligament, (Ligamentum Palpebrale Externum.) 
On the side of the internal canthus of the orbit there is no corres-. 
ponding ligamentous expansion, but a few irregular fibres, which 
allow the masses of fat beneath to project forwards between their 
fasciculi. 

The Palpebral Cartilages (Tarsi) are two in number, one at the 
margin of each eyelid, to which they communicate a smooth, even 
surface, from the internal to the external commissure. They are 
between the orbicularis muscle and the tunica conjunctiva. The 
upper one is larger than the lower, resembles an oval cut in half in 
its long diameter, and is about six lines broad in its middle : the 
lower one is of a breadth, nearly uniform, of about two lines. Their 
internal extremities cease just before they reach the puncta lachry-. 

37* 



430 NERVOUS SYSTEM. 

malia, and are attached to the internal palpebral ligament ; whicfa 
has just been described as one of the origins of the orbicularis oculi 
muscle, at the nasal process of the upper maxillary bone ; their ex- 
ternal extremities cease just before their commissure, and are firmly 
attached to the external palpebral ligament. 

These cartilages are thicker where they form the margin of the 
eyelids, and have there a slope or bevel, by which, when in contact, 
a small groove is formed on their posterior surface. From their re- 
sistance to the concentric contractions of the orbicularis, they keep 
the eyelid smooth, and favour its sliding upon the eyeball. Certain 
animals, being destitute of these cartilages ; when they wink, the 
skin, by the contraction of the orbicularis, is drawn up like the 
mouth of a purse. 

Conjunctiva. — Below the palpebral cartilage is the fourth layer of 
the eyelid, the conjunctiva. It is a white, thin and diaphanous 
membrane, in the uninflamed state. Beginning at the roots of the 
cilia, where it is continuous with the skin, it covers the posterior 
face of the eyelids in adhering almost immoveably to the tarsi carti- 
lages ; is reflected for eight or ten lines towards the bottom of the 
orbit, and then passes to the eyeball, of which it covers the anterior 
half, not excepting the cornea. At the circumference of the latter it 
suffers a little circular elevation called the annulus conjunctiva?. Its 
reflection towards the bottom of the orbit is two or three lines deeper 
in the case of the upper than the lower lid. It penetrates into the 
lachrymal passages, to be continuous with the lining membrane of 
the lachrymal sac. 

From this description, it is evident that the tunica conjunctiva has 
one surface presented against itself when the eyelids are closed ; this 
surface is lubricated and very smooth, so as to permit a free motion 
of the lids and ball of the eye. The other surface is connected in 
its anterior half by cellular substance to the eyelids, and in its re- 
maining part to the ball of the eye, by the same means. The name 
of the sclerotic fascia has latterly been used to designate this cellular 
substance, and is especially resorted to in the account of operations 
for squinting, by cutting the muscles of the eyeball. This fascia, 
or cellular tissue, may be traced to the bottom of the orbit at the 
optic foramen, and makes an investment of the several contents of the 
orbit. From this it is sometimes considered as consisting of two 
lamina? ; the exterior one being an investment especially of the mus- 



THE EYE. 431 

cles, is the capsule of Bonnetus ; while the more interior division 
being next to the globe of the eye, is the capsule of Tenon. The 
conjunctiva is united rather loosely to the sclerotica till it gets near 
the margin of the cornea ; but to the latter it adheres so firmly, and 
changes there so much in its texture, that it seems like a portion of 
the cornea. 

This membrane from its continuity with the skin and the linino- 
membrane of the nose, from its sympathies with them, from the 
nature of the discharge from it, and from its extreme sensibility, is 
ranked by Bichat among the mucous membranes. It, has, how- 
ever, some peculiarities in its structure, for it is entirely deficient in 
villosities on the eyeball, unless near the angle of reflection — but on 
the eyelids, and especially the palpebral cartilages, the villosities are 
very easily seen in an inflamed state or when ejected by an injection. 
The conjunctiva is most abundantly furnished with capillary ves- 
sels, and they do not obviously admit red blood, but in a state of ir- 
ritation ; except just among the glands of Meibomius, where most 
persons have them somewhat turgid with blood. In a minute injec- 
tion, this vascularity is fully and beautifully evolved on the tarsi 
cartilages. 

The conjunctiva has a covering of Epithelium, and is stated by 
Valentin* to be destitute of mucous follicles, the secretion of the 
lachrymal gland supplying the place of mucus. This observation is, 
however, opposed to that of Krause, who says that they are very 
numerous at the conjunctival reflection : forming little masses there, 
and then scattering as they approach the tarsi cartilages. Its epi- 
thelium is made according to Henle, of fine polyhedral nucleated 
cells. 

I 

Glandules Palpebrarum. — These bodies also called the glands of 
Meibomius, from an anatomist who has described them particularly, 
are situated at the margin of each eyelid ; between its cartilage, in 
which they are received in small grooves, and the conjunctiva. 
They are about two or three lines long, and appear like small, 
white, serpentine threads, running at right angles to the margin of 
the lid, near to, and parallel with one another. When examined 
closely it will be found that a Gland of Meibomius is a long tube 
having small ccecal tubes or cells discharging into its sides, and 

* Mailer's Physiol., p. 417. Lond., 1840. 



432 NERVOUS SYSTEM. 

which occasion the serpentine appearance. They are more abun- 
dant on the upper than on the lower lid. They terminate by a row 
of small orifices in the margin of the lid, just behind the cilia. For 
preventing the overflowing of the tears, and the sticking together of 
the eyelids, they discharge an unctuous fluid, which may be made 
manifest by squeezing them. Their secretion is occasionally much 
augmented, and then has a large quantity of serum and glutinous 
matter in it : in this case the evaporation of the serum makes it ad- 
hesive, and causes the eyelids to adhere after they have been closed 
for some time, as in sleep. 

The Lachrymal Caruncle (Caruncula Lachrymalis) is placed in 
the angle formed by the internal junction of the eyelids. It is a red- 
coloured tubercle, differing in size in different individuals, but 
commonly as large as a grain of wheat. It is conical, and obtains 
its redness from the conjunctiva being reflected over it: when ac- 
curately examined, it will be found to consist in a group of sebaceous 
glands; of which according to some anatomists, there are seven 
ranged two in a row, and one on the top of the others. The sur-> 
face of this body is beset with very fine hairs, and the orifices in it 
are distinguishable with a glass. 

The Semilunar Valve, or Fold, {Plica Semilunaris,) is situated 
immediately at the outer margin of the caruncle. It has the form of 
a triangle, the point of which runs into the caruncle, and the base, 
which is somewhat crescentic, is directed towards the eye. It is a 
duplicature of the conjunctiva ; becomes very manifest in an exami- 
nation from behind, and, in some persons, has its base furnished 
with a very small strip of cartilage.* I have seen several cases of 
the kind very well marked; they occur more frequently in the 
African, according to my personal experience. Between the base 
and the caruncle this fold is formed into a number of small loose 
wrinkles, which disappear when the eye is very much abducted. 

This body, in the human subject, is evidently intended to permit 
to the eye a great freedom of abduction. Its analogy, however, 
with the third eyelid of animals is very striking, and the difference 
is rather in the full development of the latter, than in the organiza- 
tion. It is very properly remarked by J. F. Meckel, that in de- 

* Meckel. 



THE EYE. 433 

scending the scale of animals, the third eyelid is always in an in- 
verse ratio to the other two, till it ends by being a complete substitute 
for them. 

Surrounding the Lachrymal caruncle may be observed a de- 
pression on the adjoining part of the plica semilunaris. Into this 
depression the puncta lachrymalia are directed, and there play up 
and down. The tears accumulate in it ; from which cause the de- 
pression is called Lacus Lachrymalis. 



Muscles. 

The Musculus Levator Palpebral Superioris is placed in the su- 
perior part of the orbit. It arises by a small round tendon from the 
upper margin of the optic foramen, and, becoming fleshy, it ex- 
pands itself into a long thin triangle, of which the base is in front. 
It covers the rectus superior muscle. 

Terminating in front by a thin tendinous expansion, it is inserted 
into the superior margin of the upper palpebral cartilage ; but some 
of its fibres continue on between the latter and the orbicularis to the 
lower edge of the cartilage. 

It raises the upper lid, by drawing it towards the bottom of the 
orbit. 

There are six muscles concerned in moving the eyeball, four of 
which, from their direction are said to be straight ; and the other 
two, for the same reason, are called oblique. With the exception 
of the inferior oblique, they all arise from the bottom of the orbit. 
Being inserted tendinously into the Sclerotica, their tendons pass on 
for two lines or so in continuing this connexion beyond its com- 
mencement. 

1. The Rectus Oculi Superior, being placed immediately below 
the levator palpebrse, arises from the superior margin of the optic 
foramen. It runs forwards, increasing somewhat in breadth, and 
is inserted by a broad thin tendon into the sclerotica, four lines from 
the cornea. 

It turns the eye upwards. 

2. The Rectus Oculi Externus arises from the external margin of 



434 NERVOUS SYSTEM. 

the optic foramen. It then advances along the middle of the ex- 
ternal wall of the orbit, near the periosteum, to which it adheres 
slightly ; and is, finally, inserted, by a thin broad tendon, into the 
external side of the sclerotica, about four lines from the cornea. 
It abducts the eye, or turns it outwards. 

3. The Rectus Oculi Inferior arises also from the optic foramen, 
at its inferior margin, and, lies upon the floor of the orbit as it ad- 
vances forwards. It is inserted, tendinous, into the under surface of 
the sclerotica, three lines from the cornea. 

It depresses the eye, or turns it downwards. 

4. The Rectus Oculi Internus arises from the internal margin of 
the optic foramen, and goes forwards along the internal wall of the 
orbit, being separated from it by a layer of adipose matter. It is 
inserted, by a tendinous expansion, into the inner side of the scle- 
rotica, three lines from the cornea. 

It adducts the eye, or turns it inwards. 

5. The Obliquus Oculi Superior is placed along the upper in- 
ternal angle of the orbit. It arises from the corresponding margin 
of the optic foramen, by a small round tendon ; it then advances 
forwards, and when it has got near the margin of the orbit, it is con- 
verted into a long round tendon. 

The tendon passes through a fibro-cartilaginous l